358 MGP

[Michael458]

My good Friend Sam Rose is always looking for a new project he and I can work on. Some months ago he pitched the 358 MGP to me. Basically it is a 6.8 SPC or whatever that thing is, taken up to .358 caliber. Sam got the barrels and actions and put together two uppers, one for him, one for me. Except on mine we didn't put the gas system in, nor the handguard, and we hooked up a strain gage on it to do pressures and load data with it. There was some load data, but that data has never really been put to the test, we decided to do our own, and do some work with a variety of different powders to see what made this thing tick. We also have access to bullets that are not available off the shelf, we wanted to work with those too. And without proper pressure data, everything is a guess...........

I put my rifle on a PSA lower I had here, BTW, 16.25 inch barrels, and a Vortex Spitfire........Then we hooked it up to the computers................

I bought basic 6.8 brass from Starline to work with. I have always found it easy to GO DOWN than to GO UP when forming a case. Easy to do, put the basic case in, size down to .358, and trim to length. Sam had 6.8 brass, and went up with his, it was Ugly! But worked out when fired.........

Here is the 358 along with a 300 BLK for comparison....

That first load data we did we looked at WW297 (MilSpec 296), WW 296, LilGun, IMR 4227, XMP 5744 and AA 1680.

We tested 200 Remingtons, 180 Speers, 180 Barnes TTSX, 158 RN FMJ (cheap bullets Sam found) and the 150 CEB Raptor brass along with the 160 CEB Maximus copper.

For Terminal Performance, nothing can touch the Raptors, they are just wicked. But the 150 CEB Raptor is a long bullet, and we are not working with a lot of case capacity. I used the faster burning WW 296 for the 150s, but still could only manage 2360 fps with 25.5/WW 296. Pressure was good, at 52000 PSI, but more powder was bulging the case.

Sam later cut down the base of the 150 Raptors to make a 125 Raptor. This worked as far as case capacity and changing to AA 1680 I was able to get 2608 fps with it at 46000 PSI with 34/AA 1680.

The all copper 160 CEB Maximus came out a little better over all on our first load data tryouts. With 33/AA 1680 we managed 2430 fps at 56900 PSI. Now my rule of thumb with these platforms is 55000 Max Pressure. However, this is considering 1000s upon top of 1000s of rounds. A cartridge like 358 MGP for our purposes would not be 1000s of rounds, so 56900 would be acceptable.

I did not care for the 200 Remington. The best we could do with it was 2100 fps at 52000 PSI. Even pushing pressures up a notch would not have been enough gain to make it more viable.

The big winner in our first load data sessions was the 180 Speer. With various brass we hit 2340 fps with it from 54800 PSI to 55700 PSI. We felt like this bullet would work extremely well when it come to Terminal performance at this velocity.

These first Data sessions we came away with AA 1680 being the top powder, and two excellent viable bullets, the 160 Maximus at 2430 fps and the 180 Speer at 2340 fps.

There was only one thing that bugged me, AA 1680 was throwing a hell of a fire ball.......

 

[Michael458]

I forget the fellows name that developed this cartridge some years ago, but very typical of these things, big claims were made about the cartridge, velocity and bullets, and has these loads publicized here and there. He asked me to try one of his loads to see what it does. It was the 180 Speer and 26/LilGun. Yep, I tried it, 2352 fps and 64500 PSI. Locked the gun up tight, had to beat the bolt out with a hammer......... Don't always believe what is published without better science behind it.

Anyway, there were a few things that we did not like. Sam never liked the short neck of the 358 MGP. It was more difficult to make from 6.8 brass. He decided a longer neck would be easier to form and make, so he had Dave Manson make a reamer for the longer neck version. This way, just size the 6.8 case, take it up, and then trim the excess to fit in the 6.8 magazines. This is what Sam did. It did not change the case capacity or cartridge enough to make a difference, except a better looking cartridge, more neck tension and so forth. No new load data required. I have not gone that way, yet anyway. I am sticking with the 358 MGP as is. I don't plan on doing that much with the cartridge, so I will take it as is and roll on.

But the big fire ball coming out with AA 1680 did not suit me. Sam found some Shooters World Powder, and I had bought some CFE Black. These were close to AA 1680 in burning rate, so I figured to give them a go and see what we came up with.

With the 180 Speer 34/Shooters World gave us 2341 fps at 54300 PSI. No Fire Ball. Very much equal to the AA 1680 load, but without the fire ball. So that is a success.

Again, the 180 Speer (I bought 500 of them) with 34/CFE BLK gave 2379 fps at 55300 PSI, and NO FIRE BALL............. Again, a success...........

With the 160 Maximus from CEB results were similar 34.5/Shooters World 2426 fps 54900 PSI and 35/CFE BLK 2482 fps 55200 PSI.........

I had rid ourselves of the Fire Ball with these two powders, no extra pressures, and a tiny bit gain in velocity with the CFE Black........... Progress............

Now it was time to decide on which bullet to use the most and what would give the best overall Terminal Performance............

 

[Michael458]

Now everything comes down to the bullet. How does one enhance any cartridge? The Bullet. The bullet is everything. Use shit bullet, get shit results. I am not talking punching paper targets.

Both Sam and I felt really good about the 180 Speer. So many advantages. Common, very reasonable price wise, easy to get. We were getting great accuracy and good velocity at 2340 fps. We did not believe that was too fast, or too slow to get good terminals.

But we both also know exactly what a Raptor does, but not a lot of experience with the Maximus from CEB. Our velocity with the 150 Raptor was only 2350 fps, while it would work very well, we just wanted more velocity. Both with the Maximus and Raptor. So Sam cut some 150 Raptors down to 125 grains and the 160 Maximus to 137 grains. Both these were giving 2600 fps in the 16 inch guns.

The only way to know things for sure, is to test them. So we set aside a day to get this work done here on the range. Test medium we have used for nearly 20 years or more is wet news print with 30-35% of that medium being magazines and catalogs, making the medium much tougher. It is soaked down for a minimum of 24 hours to make sure it is aqueous all the way through. Wet is the only way to test a bullet for terminal performance. Critters are wet, not dry..........Bullet BEHAVIOR is exactly the same in this test medium as it is in Animal Tissue. Penetration is not the same, test medium is far more dense than animal tissue. But I have done enough of both to be able to correlate the data...........

Here are the results.....................

The 180 Speer Giving MORE than adequate penetration for its mission, very good trauma to tissue/test material. Penetration between 15-17 inches in this medium is very good.



Next up is the 160 Maximus from CEB. This bullet also fits the case/magazines perfect, loads easy and feeds in these guns great.
It produced excellent trauma, and as you see here the blades sheared at two inches, starting to rip and tear medium, very similar to the Raptors.

The blades, possible petals in this case….. Tend to stay closer to center of wound channel. Here they did not radiate far from center like the Raptors. Since I have not tested or worked very much with the Maximus, I am not sure if this is a tendency of the copper and the design of the bullet, or if in this case it is caliber. We all know that the smaller caliber Raptor blades are not large enough to radiate too far from center. But, I tend to lean towards bullet design, and material keeping blades closer. And, nothing wrong with that at all, it produces large center wound channels.

Below are the 137 gr Maximus that Sam cut down. Trauma really was not any better than the 160 Maximus, even with higher velocity. In the end, it is our opinion that there is really nothing to gain by going with a lighter Maximus bullet, and the 160 did as well in all departments, and a bit better in penetration because of the heavier remaining bullet.

Below is the 125 Gr Raptors that Sam made from the 150s....................Trauma inflicted in the test medium was MASSIVE

No doubt as to what the BLADES from these were doing as well, you can see it in the test medium........

As you can see, penetration much less than the other bullets, to be expected with a 66 gr Base. Massive trauma inflicted to the test medium.
But as good as it is, in this case the penetration is just a tad short for ALL AROUND USE. This would be an incredible destructive Zombie/Taliban whacker, and it would be what I wanted for HOME DEFENSE with the rifle laying around waiting for Zombies to knock on the door, this is THE BULLET. But for all around use, hunting, and such, I think I want a little more penetration on other critters……..

This would be a special order bullet, and I have done plenty of that over the years, so not really a big issue. One would order up 250 of them, they would be easy to CNC with a batch of 150s anyway. Just a little shorter. However, in this case I am not going to do that for this cartridge. For my purposes overall, I believe I can get by with the 180 Speer, and if I needed MORE, then I would go with the 160 Maximus which is already in production.

From this test we proved that the common 180 Speer would do a very good job for the things you would use a 358 MGP for. I would consider the 180 Speer the GO TO Bullet for the cartridge. If one wanted a little more trauma inflicted, then you can have a couple of magazines loaded with the 160 Maximus. No special bullet needs actually required.

I have not put my gun back together, and will probably keep it for some time as a test gun in case I want to do more load data on something. It has been a fun project and as always we learn something new on every project. I think this is about the first time I have ever recommended just staying with a common Conventional bullet, at least for all around general use. But that is the case with this one.

 

[ronn47]

Michael,
Would you explain your pressure testing setup sometime?
I've read a little over the years about people using it but nothing really on how it works.
Thanks,
Ron

 

[Michael458]

Would you explain your pressure testing setup sometime?

I could do a book on it. But I will try to give you a brief over view of it, which will be difficult. I actually would rather do a complete thread down on reloading, but I don't have the time today or this week to do so..... maybe later......

Here we go...........I actually have some of this info on the B&M Website.... so I can do a little paste/copy and maybe add some things.............

Pressures are very important to the hand loader. And somewhat of a mystery to most of us. There are so many variables involved, that there are very very few absolutes……

Ken Oehler says this at the very beginning of the System 83 Manual.

Chamber pressure measurement is a blend of science, black art, and common sense. There are few absolutes; the best we can expect is to reliably distinguish between the safe and the unsafe. Pressure measurements are tedious, but they must be made. Pressures will literally rise up to smite the unwary.

You Must Understand This………. And take it to heart, when considering Pressures…. All Pressures, From ANY SOURCE………

You may read that the pressure of a certain load is 56,000 psi. You must not assume that the 56,000 psi is an absolute number. The 56,000 psi number by itself does not tell you the pressure that will be generated when you fire the ammo in any specific test barrel or gun. The pressure generated by the round depends greatly on the gun in which it is fired and the test conditions. Individual chamber and barrel tolerances are critical. The pressure numbers so casually mentioned with great authority are not absolute; they are approximate and they are only relative!

The pressures measured in any specific gun with the either piezo transducer or strain gage apply only to that gun. You can use the pressure numbers to compare different ammo fired in the same gun with the same instrumentation. Strain gage readings from the M83 correspond closely to pressures in hundreds of pounds per square inch. Pressures in sporting gun will typically be lower than pressures of the same ammo fired in a standard test barrel because the test barrel is intentionally made tighter than typical sporting barrels. Just as some barrels shoot accurately and some won’t, the same ammo builds different pressures in different barrels.




I have been running pressures here since around 2003-2004 as I recall. Using a little known tool called Pressure Trace 1 from RSI, and Jim Ristow. It was a major pain in the ass going through the learning curve, with very little help. Ristow really did not know as much as he thought he knew about pressures and his own unit. In the beginning I was running several rifles, 358 STA, 458 Lott, 458 Winchester, and several others in the early years. On many rifles I would get a incredible secondary peak, Primary or first peak would be normal, anything from say 60000 PSI or so, Secondary would go to 100000 PSI or more???? What in the world? Crazy. I did not know, did not like it, so one day I spent about 6 hours on the phone with Ristow about this. He went on and on about this or that, today I know now, he did not know anymore than I did about it.

Of course there was no such thing as having a secondary peak out there at 100000 PSI or more, in the end it was just electrical is all. The 358 STA was the worst at giving a large secondary, I decided to change the gage and redo it, and low and behold, the peak went away! Today, anytime I start getting that secondary peak, larger than primary, its nothing but a wire, or a gage or something such as that, nothing more.

Now, with that being said, sometimes there are actual secondary peaks, small ones that bump up as the bullet exits. This occurs with CERTAIN BULLETS most of the time. For instance, Hornady DGS and Swift A Frames have small secondary bumps at the end of the curve in most calibers. While other bullets in the same caliber do not. Strain gages are very very sensitive, and if you have the right software that you can see the curve and what it does, then you can learn a hell of a lot.

I really had no idea in those early years just how damn good Pressure Trace 1 is, or WAS I might say. There is no more Pressure Trace 1 units available. Ristow is a decent software fellow, but hardware he is not. Some older fellow actually built Pressure Trace 1. Then he DIED! And everything about Pressure Trace 1 he took to the grave with him! Ristow had NOTHING after that, with the exception of spare parts and what few units were on the shelves! THE END. I had fired literally 1000s upon top of 1000s of rounds through Pressure Trace 1, and had sent it back several times to have small connection parts replaced, as they would loosen up, and start causing issues with reading the pressures, loose wires, connections, and so forth.

I did all the B&M work with PT 1. Starting from ZERO basically. There was nothing to go by, no known powders, pressures, and I also had to learn exactly how RUM and WSM brass worked to even study the brass. Using PT 1, and comparing brass measurements, and by listening to what the rifle said to you, how it reacted with bolt lift, I really started to believe more strongly in PT 1 and what it was telling me. Between PT 1, and the other indicators, I found everything was matching up very very close.

Here is a photo of Sam when we were doing some pressure work with the double rifles, using PT 1………….. Very Simple little unit, but tells us so very much……….

By the last time I sent PT 1 in for repairs, I was told I had the very last of the spare parts, there were no more to be had, none that could be made, that was it. By then I had finally learned that PT 1 was absolutely a Stand Alone System, in other words, it was so good that the readings you got from it were real, and no calibration or anything required, if you had good gages, wires, and good connections! Today, I know that PT 1 for $500 back in the day, is every damn bit as good as my $12’000.00 Oehler Unit! Had someone been smart, PT 1 would OWN that market today! In fact, when it comes to software, and the reports, the RSI Software is Far Far Far superior to the Oehler much OUTDATED software. You can learn more from the PT units than the Oehler Software can show you looking at the curves! Here are examples of the reports I see……….. Judge which one is better for yourself!

Oehler System 83 Report......

Nothing really wrong here, you get the correct Pressures, you get a Stand Alone System, what you see is what you got!… But, when compared to the PT Software, to me, this really comes up short……………

I have run the PT Software so much, one can really see what is going on with the Curve, and how things work, burn, and what is happening in there! Here is a very nice test with 416 B&M……….. These are the kind of tests I really love to see…………

You can see there is a hell of a lot of difference between the two Software systems. To me, the Oehler is for SHIT! Other than stand alone and give you something to work with……….

 

[Michael458]

The first post was so large it would not post........ I had to cut it down to half..... HEH.............. Here is the rest of the post.............

With the last of the spare parts used up for PT 1, I was beginning to get concerned about being able to continue to work with pressures. If something happened to PT 1, I was screwed, along with all the data I had collected. I decided to get a new Pressure Trace 2 unit and see how that worked.

Pressure Trace 2 was built AFTER PT 1 was no longer a viable product. It did away with the wired connection to the computer, and uses Bluetooth to exchange the data from the strain gage, to the computer…….. I never liked bluetooth anything, but there was the PT 2, or the Oehler, and I was not ready at that time to commit to the Oehler! PT 2 cost a bit over $500, not a big investment. So, I got one on the way, but then it would not connect, no matter what I did I could not get the damned thing to work. Back to RSI! They checked it, said it was fine, sent it back, again it would not work, or connect…… This went on for weeks, email and phone back and forth. Finally I had enough of this BS, told Jim I was sending the unit back, they buy a laptop for me, set the damned thing up, get it to working, then send it back. Now this is after sending the unit back a time or two, along with my laptop I already had for PT 1, this was the last straw! It had finally gone 7-8 months of aggravation. At one point I told Jim I would just as soon put the unit downrange and blow it all to hell as to mess with it anymore! And I meant every damn word of it, and it came close…………

Finally, got the unit back, with its dedicated laptop, THEY SET IT UP, and it actually worked! Oh, by working I mean I could get a trace, but it was NOT CORRECT. I had known pressures, in particular in the 50 B&M Alaskan Marlin I had been using. This gun talked really good, it locked up at 46000-47000 PSI, so I knew what max loads were in this gun. A 44000 PSI load showed about 25000 PSI on the PT 2, so I knew this was bull shit from the beginning. According to RSI however, the PT 2 was RIGHT……. There were some serious debates and arguments over this, some which ended again in blowing this POS all to hell and calling Oehler!……. HEH HEH…. What a mess……… OK, fine, no need to argue, I actually know more about this than they do, so I just dropped it and figured out how to calibrate PT 2 with PT 1. When I figured out how to do that, then PT 2 worked great from that point. PT 2 IS NOT A STAND ALONE UNIT, it has to be calibrated to a known pressure. Once I had a rifle/cartridge calibrated, then PT 2 was a viable unit.

Now, all I had to calibrate PT 2 was with Prior tests done with PT 1, OR use PT 1 for the Unknown, and then Calibrate PT 2 from that point. What the hell would I do if PT 1 went down for the final time? On any new work, any new rifle or cartridge, I would have no way in hell to calibrate PT 2, so it would be lost as well….. and useless…………..

Time to bite the big bullet if I wanted to continue any sort of research, and I do love doing these sort of things, and having that capability, so I started talking to Oehler!!!!!!!

Oehler, the industry standard…… I got a good dose of “STICKER SHOCK” you might say….. The first quote I got, System 83, with chronograph, no ballistic downrange targets and all that mess, don’t need that…. was around $12’500.00

OUCH…….. I had not requested the chronograph, so we negotiated that OUT, and got the price down to a bit more than $10’000.00, so I ordered one. Now I got some more surprises too, disappointed surprises at that. Now here is a $10’000 unit, and I was going to have to make up my own strain gages? I was also going to have to make my own wire hookups? They did not even have strain gages available, I was going to have to outsource them! Unit uses a standard telephone wire and connector, so that was not going to be a big deal, but me doing the soldering and such to those tiny strain gages? No way!

Talking to the Oehler people we decided the READY MADE strain gages from RSI were the SAME exact gages they used anyway, and with those hookups the Oehler would work fine. Whew, thanks to RSI (pissed me off a little) I could use the same gages, ready made, nice connectors already made up at around $25 each! I still had to solder and connect the RSI connectors to a telephone wire, but that I could handle. And did.

They had to build my System 83, the newest and greatest from Oehler. It arrived, and actually looks like something made in the 1980s in its aluminum box! LOL…………… Much talking to Oehler, they assured me that it was a “Stand Alone System”, required no calibrations, and it would be “What you See is What You Get”………….. When it arrived, I could not wait to test it, so I had known, OR WHAT I THOUGHT WAS KNOWN, loads ready to go in several rifles and cartridges. I input all the required data, which was actually some less than what was required on the RSI systems……. and started shooting…………. I admit, I was concerned what would happen, what would I do, if the Oehler system did not match all the work I had done for 10++ years?

Within an Hour, I WAS

………….. Every reading the Oehler took, matched damn near perfect with everything I had expected and hoped for!!!!!! I WAS EXTREMELY pleased with this, all my work for years matched the industry standard equipment!

This really did show me just how damn good PT 1 was!

The box the Oehler is built around matches the software they still use, 20-25 years outdated as I figure it! Those little nothing pressure trace curves on the Oehler, you can’t learn much from those. The RSI software was light years ahead, in my opinion anyway. But, it does make the Oehler easy to work with, and very few issues……….

None the less I finally had all my systems here worked out. I now use the Oehler to obtain stand alone data and calibrate PT 2 from the Oehler. Once that is done, PT 2 runs great, especially when I want to look at how things are burning and what the curve is doing. You will be amazed at what can be learned just by studying the curve and how it reacts……. I really enjoy running pressures, lots of work, but very rewarding in the end…… Regardless of how you do pressures, its all still just an estimate, in this case I feel like its a very close estimate, but not an absolute.

Fortunately in the B&M rifles they are all done with the same barrels, same reamers, same builders–SSK Industries. While not a clone copy in every case, they are very close from what I have seen. Other rifles, different chamber specs, different barrels and so on, best you can hope for is that the data is in the ballpark, maybe close in some cases, but one should always move smart and safe by starting under any published data, mine or anyone else’s………

While there are few absolutes, there are some rules you can go by….. One is Weight Always Equals Pressure! The heavy bullet will always take more pressure to move than a lighter one. Use the same load, heavy will give more pressure. Bearing surface equals pressure! The more bearing surface a bullet has, all else equal, the more pressure it will produce. Diameter equals pressure, all else being equal in the same caliber, a .001 more will give more pressure…….. These three things are absolute in most all cases……..

Pressure Trace 2………… And the Oehler………

 

[Michael458]

Below are some Sample Traces that we have done...................

There are 1000s more of these on file.............. Those are just samples of a few to give you an idea.....

Over the last couple of years I have been very lazy to hook up and run the PT 1 or PT II Systems. I now have two very "Coveted" PT 1 Systems that are fully operational. As Stated, PT 1 is an absolute Stand Alone system and gives you real time pressures, exactly the same as the Oehler 83. PT II has to be CALIBRATED to that particular rifle. One gets real time data from either PT 1 or the Oehler, and then calibrates that to the PT II. From that point on with that RIFLE, then PT II is operational and gives real time data. And great reports, same as PT 1.

But I have been LAZY for the last two years at least. Its just easy to go turn on the Oehler, hookup, and get the basic data I need. And, I am very protective of the PT 1 Systems and won't hook them up, since nothing can ever be replaced on them............

Yeah, I know this is way more than you wanted, but this is the brief version............. LOL.........

Hope that helps answer a few questions, but probably creates more..............

Michael

 

[ronn47]

Thanks, I appreciate the write up, even though I don't understand 98% of what I am looking at I want to try and learn.

 

[Michael458]

Thanks, I appreciate the write up, even though I don't understand 98% of what I am looking at I want to try and learn.

Yeah, I get it. I copy/paste most all of that from elsewhere, so it is a LOT of info, fast...... LOL................ If that don' t basically cover your question, don' t be afraid to ask more............. I love doing pressures, it is an entire world
unto itself, and you learn a hell of a lot from it.......

There are special projects that Sam and I worked on specific to Double Rifles, and barrel strain of different bullets. This comes from some bullets being blamed for separation of barrels and so forth like that......... It was accomplished using strain gages that were attached 4 inches back from the muzzle of the rifle which measured in PSI the amount that the barrel expanded at that point. Giving us reference from one bullet to the next. We were able to design the bands on the CEB and North Fork bullets this way, reducing barrel strain, and chamber pressures as well with full caliber bands reducing the amount of bearing surface.......

We have used these machines to do a lot of things that have never been done before, and the product we came up with is now industry standards......... So it is a lot of fun to be able to do things like that.........

 

[BatteryOaksBilly]

I so hope that the membership takes advantage of the resources we now have with Mike's participation. He has helped many Loaders of commercial ammo get product to market. There aren't many folks that would spend 10s of thousands of dollars in equipment and then 100s of thousands of dollars in time just to GIVE it away. In my Small way I try to contribute to the handgun shooting community, Nothing like Mike does.
Ya'll can't get this info from anywhere that the giver isn't hoping to make Something off it. Not even folks like Lucky Gunner who are in it to sell product can give you This kind of info.
We are Pards for almost 40 years and I have never seen him make a penny off anybody. For guns, ammo, or info. Amazing in this day and age.

 

[Michael458]

Really this stuff needs to be in a separate thread down on reloading............... This 358 MGP thread will fade in short time......... Not many shooters really understand pressures and some aspects of serious hand loading, and how it effects everyday common things you do..............

We have done some seriously interesting projects and learned a hell of a lot doing them. One current project we are working on with RCC Brass in Texas could change the brass cartridge industry completely. But you never know until you do the test work, and as soon as the material is ready, we will be doing that test work here. Some other things we have studied is if it were possible to imprint the rifling of a barrel to the "outside" of the barrel. Something claimed by double rifle shooters, concerning hard monolithic bullets. Well, Sam and I could not do it here, using a .458 caliber barrel, the thickness of 5 sheets of paper, and over sized STEEL bullets. Interesting stuff, crazy, but damned interesting..... LOL........ And many other things..................

Glad to help if I can.......... lets hope its a bit better than what you pay for... LOL..........Billy, too kind...........

 

[BigWaylon]

Really this stuff needs to be in a separate thread down on reloading...............

Want me to move these last several posts to a new thread in the reloading section? And I can put a link to it in this thread?

 

[Michael458]

Want me to move these last several posts to a new thread in the reloading section? And I can put a link to it in this thread?

No, maybe in the morning I will organize a thread on Reloading..........Thanks however........... Want to organize in a way that tries to make better sense, and able to add this into it as it goes...........

 

[Bushwhack Benny]

No, maybe in the morning I will organize a thread on Reloading..........Thanks however........... Want to organize in a way that tries to make better sense, and able to add this into it as it goes...........

Michael, are you still working with the 358?

This is fascinating to me, if nothing else - thanks for the education!

 

[Michael458]

Michael, are you still working with the 358?

This is fascinating to me, if nothing else - thanks for the education!

Well I would not say I am still "working" with it, indicating that I am still doing any development with it. Fact is, I have it, I like it, I settled on a more common bullet that really did a good job, and plenty good enough for any purpose I might have with the rifle, and that is the 180 Speer Hot Core loaded with CFE BLK to 2358 fps. I have the rifle in the Lab, full magazine, and two extra magazines with it......... And 250 rounds loaded ready to shoot........... I did recently change the scope on it to a small extra 1X4 Leupold I had laying around, that had not yet been busted to pieces by one of my big bore rifles. It's a perfect fit, and it should be ok on this gun. Sighted in 1/2 inch high at 50 yards, and RTG! (Ready to Go)..... when needed.............

Recently my shooting/hunting partner Sam used his on a 350 lb bear that was raiding his bee hives, to good effect I might say as well...............Using the 180 Speer load.

 

[Bushwhack Benny]

Great to know.

Is there anywhere to get a barrel and dies?

Looks like MGP Customs no longer has a website...

 

[Michael458]

Great to know.

Is there anywhere to get a barrel and dies?

Looks like MGP Customs no longer has a website...

My Buddy Sam was the one that sorted all that out. He got two barrels and die sets when he put our guns together, he took care of all that and I had nothing to do with it. He contacted the fellow direct.

Sorry, I have no info on it........

 

[Button Pusher]

I so hope that the membership takes advantage of the resources we now have with Mike's participation. He has helped many Loaders of commercial ammo get product to market. There aren't many folks that would spend 10s of thousands of dollars in equipment and then 100s of thousands of dollars in time just to GIVE it away. In my Small way I try to contribute to the handgun shooting community, Nothing like Mike does.
Ya'll can't get this info from anywhere that the giver isn't hoping to make Something off it. Not even folks like Lucky Gunner who are in it to sell product can give you This kind of info.
We are Pards for almost 40 years and I have never seen him make a penny off anybody. For guns, ammo, or info. Amazing in this day and age.

I consider Michael and Billy 'Professors'.

 

[MGP]

I forget the fellows name that developed this cartridge some years ago, but very typical of these things, big claims were made about the cartridge, velocity and bullets, and has these loads publicized here and there. He asked me to try one of his loads to see what it does. It was the 180 Speer and 26/LilGun. Yep, I tried it, 2352 fps and 64500 PSI. Locked the gun up tight, had to beat the bolt out with a hammer......... Don't always believe what is published without better science behind it.

Hi Michael ,
I would like to know what big claims were made that my 358 MGP did not live up too ?

Let me say great work on all the testing you have done. I know i never sent you my rounds i was very sick but i can send them to you now
if you would like ? What i found weird is that 26/Lilgun Load with 180gr Speer Hot-Core you said it locked your gun up. I've not had any pressure signs I've
even tried 27/Lilgun with no pressure signs 27/Lilgun was just not accurate. I'm going to test your loads when i can find the same powder just to see if i find similar
results. I'm wondering if it just was a different Lot of powder that was hotter? That's the only thing i can think it could be.

Oh and how did Sams round work out? I have tested this round in a bunch of configurations and for me the long neck was not as accurate as the short neck.
The short neck is plenty to hold the bullet tight enough.
I designed this round for 3 bullets 180gr Hornady SP which has been discontinued , the 180gr Speer the toughest bullet for my 358 MGP and the Hornady
200gr FTX. Which my hunting load for the 200gr FTX is 23grs/Lilgun and the best group was .352'' 5 shots at 100 yards and with that load i had a difference in
2 different lots of Lilgun when i first tested it i was getting an avg of 2100fps then i ran out of powder so the next pound of lilgun was a different lot and when
tested that lot i was only getting a avg of 2018fps.

 

[MGP]

Great to know.

Is there anywhere to get a barrel and dies?

Looks like MGP Customs no longer has a website...

Hi ,
If you are interested in a barrel and die set email me at [email protected] Thanks Mike

 

[Michael458]

Let me say great work on all the testing you have done. I know i never sent you my rounds i was very sick but i can send them to you now
if you would like ? What i found weird is that 26/Lilgun Load with 180gr Speer Hot-Core you said it locked your gun up. I've not had any pressure signs I've
even tried 27/Lilgun with no pressure signs 27/Lilgun was just not accurate. I'm going to test your loads when i can find the same powder just to see if i find similar
results. I'm wondering if it just was a different Lot of powder that was hotter? That's the only thing i can think it could be.

My Powder is Not Your Powder.......... I can't tell you how many times I have run across that, and it does not have to even be a different Lot# either, it can be from the same lot# and different kegs......... The RL powders are the worse, but it can be any of them. LilGun can be a very strange powder regardless anyway. I use a lot of Lilgun in various cartridges, in fact loading it today in 50 B&M Super Short............

Brass needs to be considered as well, different brass can give vastly different results........ So there are a multitude of variables to be considered...........

I tested my Lilgun and new Starline brass that I made from basic. With the 180 Speer and 26/LilGun it gave 2352 fps at 65400 PSI, and locked the gun up each time.

You very easy could be using a different brass, and your gun MAY NOT SHOW pressure signs....... but that don't always mean the pressure is not there. That load is over max pressure, IN MY GUN that day and would be on this day as well.

Personally I think Lilgun is a bit too fast for this cartridge, we moved completely to CFE BLK and Shooters World. 180 Speer, 34.5/CFE BLK 2379 fps at 55300 PSI........ I like to run around 55000 in these type guns.......Works perfect, shoots great.

i had a difference in
2 different lots of Lilgun when i first tested it i was getting an avg of 2100fps then i ran out of powder so the next pound of lilgun was a different lot and when
tested that lot i was only getting a avg of 2018fps.

My point exactly....... I blend most all powders, especially ones I use a lot of. 15-20 lbs, pour it in a 5 gallon bucket, stir and mix, and repackage and relabel, and retest that lot. That is my lot, my blend and when it runs out, have to do another blend/mix.

I liked the lighter 180s better than the 200s. We tested WW 297, WW 296, LilGun, IMR 4227, and AA 1680. Of those, AA 1680 gave the best and most consistent at over 2100 fps with the 200s, but with a huge muzzle blast. This is what turned us on the CFE BLK and Shooter World. Nearly the same as AA1680, without the muzzle flash........ I was not so turned on with the 200s, so didn't waste anymore time on them.

Overall, I liked the 180 Speer the best for overall work, we did Terminals on those as well of course.

Sam and I did investigate the CEB Maximus and CEB Raptors........The 150 Brass Raptor is actually too long for the 358 taking up way too much case capacity. Sam cut some down to 125 gr and they worked really well, but was just a little short on penetration, massive trauma and was able to hit 2600 fps with it......... but at 125 gr it would have been a special order and design, and just was not worth it in my opinion.

The other bullet that is available is the 160 Copper Maximus from CEB, its a Super bullet for the 358. As is, no modifications. We ran it to 2480 fps at 55000 PSI and its wicked..........

Oh and how did Sams round work out?

I think he likes his longer neck version, going back to memory that is what he did I believe. I did not, I was plenty satisfied with your original design and have no issues with it......

Its good to see you @MGP .............I like your cartridge, its one of the few that Sam got me interested in to play with. Currently all the strain gages have been removed and we put the gun together. It had to be used as a single shot to do the pressure work. I bought some extra magazines, loaded up about 250 rounds with the 180 Speer and roll on with it...........One day I may get some more basic Starline and make some with the 160 Maximus as well.............

Sam got interested in doing the .308 version with the 6.8 case. We did some data with that not too long ago, and its good stuff as well. But I am heavily invested in 7.62X40, so I did not go that route either.

 

[MGP]

My Powder is Not Your Powder.......... I can't tell you how many times I have run across that, and it does not have to even be a different Lot# either, it can be from the same lot# and different kegs......... The RL powders are the worse, but it can be any of them. LilGun can be a very strange powder regardless anyway. I use a lot of Lilgun in various cartridges, in fact loading it today in 50 B&M Super Short............

Brass needs to be considered as well, different brass can give vastly different results........ So there are a multitude of variables to be considered...........

I tested my Lilgun and new Starline brass that I made from basic. With the 180 Speer and 26/LilGun it gave 2352 fps at 65400 PSI, and locked the gun up each time.

You very easy could be using a different brass, and your gun MAY NOT SHOW pressure signs....... but that don't always mean the pressure is not there. That load is over max pressure, IN MY GUN that day and would be on this day as well.

Personally I think Lilgun is a bit too fast for this cartridge, we moved completely to CFE BLK and Shooters World. 180 Speer, 34.5/CFE BLK 2379 fps at 55300 PSI........ I like to run around 55000 in these type guns.......Works perfect, shoots great.


My point exactly....... I blend most all powders, especially ones I use a lot of. 15-20 lbs, pour it in a 5 gallon bucket, stir and mix, and repackage and relabel, and retest that lot. That is my lot, my blend and when it runs out, have to do another blend/mix.

I liked the lighter 180s better than the 200s. We tested WW 297, WW 296, LilGun, IMR 4227, and AA 1680. Of those, AA 1680 gave the best and most consistent at over 2100 fps with the 200s, but with a huge muzzle blast. This is what turned us on the CFE BLK and Shooter World. Nearly the same as AA1680, without the muzzle flash........ I was not so turned on with the 200s, so didn't waste anymore time on them.

Overall, I liked the 180 Speer the best for overall work, we did Terminals on those as well of course.

Sam and I did investigate the CEB Maximus and CEB Raptors........The 150 Brass Raptor is actually too long for the 358 taking up way too much case capacity. Sam cut some down to 125 gr and they worked really well, but was just a little short on penetration, massive trauma and was able to hit 2600 fps with it......... but at 125 gr it would have been a special order and design, and just was not worth it in my opinion.

The other bullet that is available is the 160 Copper Maximus from CEB, its a Super bullet for the 358. As is, no modifications. We ran it to 2480 fps at 55000 PSI and its wicked..........


I think he likes his longer neck version, going back to memory that is what he did I believe. I did not, I was plenty satisfied with your original design and have no issues with it......

Its good to see you @MGP .............I like your cartridge, its one of the few that Sam got me interested in to play with. Currently all the strain gages have been removed and we put the gun together. It had to be used as a single shot to do the pressure work. I bought some extra magazines, loaded up about 250 rounds with the 180 Speer and roll on with it...........One day I may get some more basic Starline and make some with the 160 Maximus as well.............

Sam got interested in doing the .308 version with the 6.8 case. We did some data with that not too long ago, and its good stuff as well. But I am heavily invested in 7.62X40, so I did not go that route either.

I was using Hornady 6.8 brass i haven't tested with the starline brass im going to see if there is a difference in H2O volume
I feel the same about the 180gr Speer Hot-Core its a tough bullet and i believe its the best bullet for the 358 MGP.

But i still would like to know what big claims were made that my 358 MGP did not live up too ?

 

[Michael458]

But i still would like to know what big claims were made that my 358 MGP did not live up too ?

All you guys that develop a cartridge make the claims about getting a particular bullet to a particular velocity.......... Not just you. And, I don't doubt you at all, I believe you got the velocity you stated with the load you stated, and I believe that
you did not see pressure signs. I believe every word you said, and I believe you got the results you said you got. That is NOT in question. The thing is, you did not have pressure equipment hooked up to your guns, and while it may have appeared you have no pressure, that may very well not be correct.................

Every gun is different, and YOUR gun may have handled that load just fine........ with YOUR POWDER, YOUR BRASS, Your Components.......My gun will not, and the pressure with that load, with my components gave over 65000 PSI and locked the gun down... Obviously over pressure.

@MGP I have developed myself 13 or more big bore rifle cartridges for bolt, lever, single, and semi guns and believe me, without real time data, some of those were OVER MAX PRESSURES, but was safe as rain in a particular gun. Moving to another gun, those same loads would lock it down tight...........I had to adjust that data before turning it loose...... I have seen it time and time again,.................Don't be offended by that statement, I have had it happen to me as well........

I am fortunate, I have the means and the equipment to do this sort of data..................Even correcting my own mistakes along the way......

 

[MGP]

All you guys that develop a cartridge make the claims about getting a particular bullet to a particular velocity.......... Not just you. And, I don't doubt you at all, I believe you got the velocity you stated with the load you stated, and I believe that
you did not see pressure signs. I believe every word you said, and I believe you got the results you said you got. That is NOT in question. The thing is, you did not have pressure equipment hooked up to your guns, and while it may have appeared you have no pressure, that may very well not be correct.................

Every gun is different, and YOUR gun may have handled that load just fine........ with YOUR POWDER, YOUR BRASS, Your Components.......My gun will not, and the pressure with that load, with my components gave over 65000 PSI and locked the gun down... Obviously over pressure.

@MGP I have developed myself 13 or more big bore rifle cartridges for bolt, lever, single, and semi guns and believe me, without real time data, some of those were OVER MAX PRESSURES, but was safe as rain in a particular gun. Moving to another gun, those same loads would lock it down tight...........I had to adjust that data before turning it loose...... I have seen it time and time again,.................Don't be offended by that statement, I have had it happen to me as well........

I am fortunate, I have the means and the equipment to do this sort of data..................Even correcting my own mistakes along the way......

Michael thank you for the explanation i understand completely. Yeah i wish i had all that equipment. That does scare me though that you got that much pressure
on the 26/Lilgun 180gr Speer I'm going to stay away from that load and get some CFE/BLK and work with that. The 200gr FTX is the most accurate bullet for the 358 MGP
but its not tough like the Speer but great for Whitetail deer and coyotes . When i originally designed this round the first test medium was a Small Block Chevrolet cast iron cylinder
head. I just wanted to see if the 180gr Speer would punch a hole through the head and it did it went completely through the head the head was standing on end i shot it between one of the combustion chamber and i got a complete pass through it was just for the hell of it.
I'm happy you're happy with the 358MGP its a hammer for such a small case. Quite a few boys from Texas have shot some huge boars with it also i read that Sam shot a 350lb
black bear with the 358 MGP.
Man those rounds look badass!!!!! Thanks again

 

[Michael458]

@MGP ............ First Class........

Will chat tomorrow, roosting time for me........

 

[BatteryOaksBilly]

When @Michael458 was doing work on the 30-30 I was so interested in he got a 100 Grain Raptor to over 3,000 FPS in a 16 inch Winchester. That same exact load LOCKED UP another Winchester tight as a Tick. He always loads Down to the safest load for the weakest platform. He has loaded some stuff especially for me that we do NOT give out to anybody. The handgun loads I carry that he has loaded are for Me only. I don't care if the cases are hard to extract or if the recoil is offensive or if it puts the gun I am carrying in potential jeopardy. I am only interested in the Maximum performance we can wring out of that gun and that load.
In the ammo industry, when he speaks.......the industry leaders listen.
My Job at B&M Rifles and Cartridges is to come up with stuff that I Want and then convince him that it's something I Really Need.
Mike's job is to provide all the R&D, weapons for R&D and Experimental projectiles and Mixed powder combinations and MONEY to buy All of that with.
See...my job is Way harder than his job.....all he has to provide is all of the Time-Weapons-Ammo-Money...I have to conjure up New STUFF!

 

[GeorgeBush]

You should pay someone to write a macro where each time you fire a round, and the results / graphs etc pop up on the screen, the computer plays the little bassline from "Under Pressure."

 

[Michael458]

30-30 I was so interested in he got a 100 Grain Raptor to over 3,000 FPS in a 16 inch Winchester.

An excellent example of what I was talking about above....... Indeed, one day I stuffed a 100 Raptor on top of a case full of H-4198 in 30/30. Went out, shot great, hit 3013 fps!!!!!! HOLY COW>.............. worked like a charm. Zero signs of pressure in the gun, or the case..... Nothing........ And yes it was a 16 inch Legendary Lawman, one of my favorite 30/30s....... Very fortunately I was busy on some other things, and I went on to something else before loading a stockpile of this stuff........One Gun, one test.......

Later I decided to get very serious about getting a load for 30/30 and the 100 Raptors. A very worthy project, and would enhance the rifle/cartridge immensely.

I dropped 3 gr of H-4198 from that first load that hit 3013 fps....... I now had the pressure equipment hooked up. Dropping three grains hit 2780 fps and 53000 PSI. 53000 PSI is about 10000 PSI over what one needs to run in a M94 Winchester action......... I also have a pile of other 30/30s and started dragging them out, and sure enough this reduced load at 53000 was locking the other guns up TIGHT............Crap, I had some serious work to do now.

Long story SHORT, as I can make it anyway............ I ran a dozen different powders and testing in 5 different guns to make sure, I settled on loads that were at or under 42000 PSI to work in all the guns. In the end, I could run AA 2520 in the 100 Flat Base Raptors no tips at 2621 fps in the 16 inch gun at 41200 PSI and safe in all the other guns as well........ It does hit 3000 fps in a 26 inch gun I have here...........But safely...........

My Job at B&M Rifles and Cartridges is to come up with stuff that I Want and then convince him that it's something I Really Need.

🤣...............Yep, that about says it all.......... LOL

 

[Michael458]

That does scare me though that you got that much pressure
on the 26/Lilgun 180gr Speer I'm going to stay away from that load and get some CFE/BLK and work with that.

@MGP Wise........ I assume that Sam sent you our data? If not, PM me and I will get it to you. Looking back on that data this morning and looking at the 160 Maximus I tried 25/Lilgun with that bullet, it also locked the gun down and hit 65500 PSI. I like LilGun.... but sometimes it can be difficult to work with, and I think, my opinion, its just not a good powder for this cartridge. AA 1680 is good, but has the muzzle flash, so we moved to CFE BLK and it works great, as does Shooters World BLK nearly exactly the same powder..... OR IT WAS................If I have to load for @BatteryOaksBilly I would have to load his with AA 1680, he' s like a damn kid, loves "FireWorks"............. LOL.......But, he does not have a 358 MGP yet......

i read that Sam shot a 350lb
black bear with the 358 MGP.

Yes........ that was with the 180 Speers as well......

 

[Lar45]

Hello, I realize this is a way old thread, but...
It looked like there was some conflicting information about max loads with the 358MGP.
I noticed the person with the actual pressure testing equipment was using starline brass.
MGP on the 6.8 forums was using S&B brass which is much thinner and gives more internal capacity.
Sorry for dragging this back up. I just saw the difference and thought I'd point it out.

 

[Michael458]

I noticed the person with the actual pressure testing equipment was using starline brass.
MGP on the 6.8 forums was using S&B brass which is much thinner and gives more internal capacity.

My Powder is Not Your Powder.......... I can't tell you how many times I have run across that, and it does not have to even be a different Lot# either, it can be from the same lot# and different kegs.........

Every gun is different, and YOUR gun may have handled that load just fine........ with YOUR POWDER, YOUR BRASS, Your Components.......My gun will not, and the pressure with that load, with my components gave over 65000 PSI and locked the gun down..

I was using Hornady 6.8 brass i haven't tested with the starline brass im going to see if there is a difference in H2O volume

Every change in components can make a difference, some small, some significant, brass indeed is one of those. Capacity makes a difference, larger capacity, with the same exact charge and all other components the same, will lower pressures, and also lower velocity.