300BLK bolt gun load testing

Jayne

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Lots and lots of data out there on 300BLK that will cycle an AR, but less so for a bolt action in 300BLK. I've picked up a Ruger American Ranch and am going to build some loads for it.

My goal is to make 3 distinct loads:

- ultra light (115 or 125gr) supersonic as fast as possible just for fun
- mid-weight (168gr) subsonic for quiet plinking (I have a lot of 168gr SMKs to burn up)
- heavy weight (220gr) subsonic for hunting, I guess? Seems like a thing.

Using just what I had on hand, I've made up the following. Brass is all once fired commercial, full sized, chamafered, etc. The lots are not all matched but it's all the same lot/headstamp within each test load. I've got a neck sizing die on the way so after this it will just be necked size ('cause bolt action). Winchester primers.

Trying for subsonic -

130gr FP - 6.4gr Trailboss
168gr SMK - 5.5gr Unique
168gr SMK - 11.5gr RE7
220gr SMK - 8.4gr Lilgun

Supersonic -

130gr FP - 17.8gr 4427
168gr SMK - 14.5gr Lilgun

I realize the 130gr flat point are not exactly ultra light or sexy, but they're left over from my 30/30 so I might as well use them to start testing with.

Long weekend ahead so I should be able to make it to the range and fire them over the chronograph and for accuracy at 100 yards.

IMG_5730.JPG
 
Check out Sierras reloading data for 300bo....it helped me figure out what i was doing wrong. When they state do not load under xxx amount, they mean it......at least for subs. My vertical stringing was ridiculous if I loaded lighter charges. From my experience with 208-225 grain subsonics.....about 9.5 grains of Win296 or H110 was the most consistent for me from a bolt rifle. The closer I could keep velocity to just under supersonic speed....the better my results. Keep us posted!
 
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I only load 8.2 of H110 under a 230 and my strings are pretty tight. Functional in my bolt and AR pistol too...
 
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Tested not only in the bolt guns, but in various semi guns as well. Have pressure data, load data, terminal data, everything.......

Post it up! I'm hoping we keep this thread bolt gun specific since the AR stuff is so plentiful elsewhere but if it works in both, who's to complain?
 
First bit of testing. Kinda bummed that the 168gr are not rock solid with whatever faster twist this gun has. Still managed a 1" group with the RE7 loading, but some of them were getting kinda 'out of round'. Oddly the 5.5gr load which was going slower actually only had a 20% keyhole rate. Tempted to do that one again, and speed the Unique load up a touch and slow the RE7 down. If that works... well they're still probably too twichy to rely on.

The absolute winner was the 220gr / Lil'gun load. 4 rounds basically touching, one dumb ass flyer 1" away from the rest. Tighten the trigger nut and that one has potential.

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Trailboss is NOT suitable for this application. Even the 6.4gr load is compressed with the short 130gr bullets, SD is over 100 (!) and... I actually got a squib. Not a true squib because there was powder, but the bullet failed to make it out of the barrel. It stuck just on the very end of the barrel, sitting inside the brake. It took just a tiny tap with the cleaning rod to get it out, but it still scared me.

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I wonder if the SD would drop on the Trailboss loads if using a magnum primer. I saw a huge drop in velocity and an increase in SD when I loaded Trailboss in 45acp small primer compared to large primer.
 
I wonder if the SD would drop on the Trailboss loads if using a magnum primer. I saw a huge drop in velocity and an increase in SD when I loaded Trailboss in 45acp small primer compared to large primer.

I would think yes. I noticed that in my super low power 357 loads, the magnum primers gave more consistent velocities.

I'll not know in 300BLK though, even 6.4 is a little compressed and that's a no-no according to all the published data on the powder. Maybe it won't generate enough to damage anything, but I suspect something bad happens or they wouldn't make such a stink about it.
 
Yesterday's results added to the chart.

The 168s are still not performing well at all. I got 1 round keyholed out of the 10 test shots, but the accuracy still sucks. Any rounds that break into supersonic get 'tossed around' and thrown out of the group it seems.

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If we can tighten up that trigger nut, I think the accuracy is there. For example, here's a 5 round group @ 100 yards of the VMAX loading:

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Get that flyer out of there and I would buy that for $1 (or $439, whatever):

IMG_5755.JPG

And when I say the 168s suck, here is what I mean:

IMG_5756.JPG

My dies are still in delivery hell, but if they ever show up I'll be able to neck size the brass for all loads moving forward.
 
Another round of testing, but no cool pictures of accuracy here because of the hurricane. It wasn't so windy that the bullets were being blown all over at 100 yards, but the targets were attached to one of those political yard sign things and it was moving back and forth a lot. At one point I was waiting for the wind at the target to die down and just as it did a gust at the bench blew the shooting mat up over the muzzle of the rifle. Would not have enjoyed putting a hole in the mat.

The chrono data is as follows. The hornady ELD is significantly longer than the sierra SMK so at the same OAL the case volume is reduced with the ELD which is why I'm presuming I see an extra 90fps with the same powder charge:

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For the next batch of the Lil'gun load I set the SMKs further in using the ELD settings on the seating die. Still not the same, but I want to see what that change does to the velocity. For my CFE BLK loads, I dropped the ELD charge down to 11.0gr since it's already too fast and I can't set it longer (at max mag length) and left the SMK at 11.2 but set the bullet back.

The difference in resulting case volume between the two 220gr bullets is pretty apparent:

IMG_5823.JPG

I know I said I was officially giving up on the 168gr subsonic, but clearly I had to try just one more time. Still keyholed and it's going as fast as it can go. So... I dropped the powder charge to 5.7gr of Unique... and stuck a 175gr smk on there. The 175gr worked in the 308 with it's slower twist so it's probably going to work here as well. I would have thought the faster twist in the RAR would have done the trick, but apparently not.

Hope to test this next batch tomorrow but I've picked up a sore throat and generally feel like crap today so I'm not sure I'll be up for going out tomorrow.
 
Another round of testing, and I think we're ready to try a few with the can on next time.

Turns out 220gr SMKs are really, really expensive and appear to not be available anywhere locally. The ELD-x are cheaper, seem to be as accurate and can be had locally if I need them. So... I'm going to not focus on the 220gr SMK load anymore. My 175gr SMK did NOT keyhole, so that's good.

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The two I made up for can testing are:

10.9gr CFE BLK w/220gr ELD
11.3gr RE7 w/175gr SMK

That should be exactly where I want. A touch slower on the 220gr than I saw last time, a touch faster on the 175gr. both hovering in the low 1000s and we're there.... if the accuracy holds. The Unique load with the 175gr was not accurate at all, so I'm not pursuing that. When the group was 4x the size of the RE7 load, I'm calling that ammo and not the shooter. :)
 
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Tested yesterday and it was an AMAZING day out. Nice temps, not humid... so basically nothing like the test conditions before. Sigh. So much for atmospheric consistency.

Data is here. My 10.9gr ELD loads were as expected. Even the peak speed of 1054 was subsonic, and the rest were not even close so that's good from a quiet perspective. Accuracy was... poor. However, now that the load is stable I'll work on my accuracy. Setting up, firing, coming off the gun, taking notes, etc between each shot makes it not so much of a 5 shot group as 5, 1 shot groups. That's a good test of my ability to get into a repeatable firing position but not so much reflective of the load.

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Next up is making a batch of the CFE BLK/ELD loads and actually trying them with the can and not the chronograph. Also have some factory 100gr v-max loads I want to test. Oddly it was cheaper to buy factory 110gr v-max loads than it was to buy new brass and load my own v-max.
 
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Loads tested today for accuracy (no chrono) with the can on were:

220gr ELD-X w/10.9gr CFE BLK
220gr ELD-X w/8.0gr Lil'Gun

The accuracy winner is the CFE BLK load, so next range trip it will just be that load and I'll just work on getting myself dialed into the rifle.

However, I can't tell if this rifle fouls quick, or I get tired, or it's heat sensitive or what but the groups seem to open up over time and the zero wanders around for both loads. It will be easier to tell next time with only one loading going down range.

I did put a legit 100 yard zero on the rifle today as well, and at 150 it's about 2 mils low. Dropping fast!

Also totally unrelated but someone left 12 perfectly good pieces of 300BLK brass in front of the bench I was using. Thanks anonymous patron of brass.
 
Loads tested today for accuracy (no chrono) with the can on were:

220gr ELD-X w/10.9gr CFE BLK
220gr ELD-X w/8.0gr Lil'Gun

The accuracy winner is the CFE BLK load, so next range trip it will just be that load and I'll just work on getting myself dialed into the rifle.

However, I can't tell if this rifle fouls quick, or I get tired, or it's heat sensitive or what but the groups seem to open up over time and the zero wanders around for both loads. It will be easier to tell next time with only one loading going down range.

I did put a legit 100 yard zero on the rifle today as well, and at 150 it's about 2 mils low. Dropping fast!

Also totally unrelated but someone left 12 perfectly good pieces of 300BLK brass in front of the bench I was using. Thanks anonymous patron of brass.

Do you neck size or full length? Subs don't fire-form. I shoot my brass with supers, then neck size the brass for subs. Less fouling and a little better consistency...
 
Do you neck size or full length? Subs don't fire-form. I shoot my brass with supers, then neck size the brass for subs. Less fouling and a little better consistency...

Full size after the first firing so I can trim them to length, neck size after that.

I probably should bring my 308 out with me next time and shoot it side by side to see if it's the rifle or the trigger nut that is causing the accuracy oddities. If the 308 isn't accurate, we know it's not it's fault. It's a proven setup.
 
Disappointing day today at the range. Accuracy was all over the place. In the first 3, 5 round strings I had a 1.25" group, a 4.5" group and then back to 1.25", all of the same load.... but 3 different types of brass.

I've noticed that some brass actually has some tension when I seat the bullet, other pieces (even in the same lot) do not. These were on their 4th firing today (full sized after first, neck sized the rest) but I wonder if they're just "wearing out"? With inconsistent POI, wild accuracy swings, etc.... perhaps subsonic loading is harder than anything else? I don't recall having this much trouble with accurate 308 and the supersonic loadings seem to do pretty well accuracy/consistency wise.

I've got a matched headstamp lot of once fired, next loads will be using that and we'll see if it's any different (and by different I mean better).
 
Disappointing day today at the range. Accuracy was all over the place. In the first 3, 5 round strings I had a 1.25" group, a 4.5" group and then back to 1.25", all of the same load.... but 3 different types of brass.

I've noticed that some brass actually has some tension when I seat the bullet, other pieces (even in the same lot) do not. These were on their 4th firing today (full sized after first, neck sized the rest) but I wonder if they're just "wearing out"? With inconsistent POI, wild accuracy swings, etc.... perhaps subsonic loading is harder than anything else? I don't recall having this much trouble with accurate 308 and the supersonic loadings seem to do pretty well accuracy/consistency wise.

I've got a matched headstamp lot of once fired, next loads will be using that and we'll see if it's any different (and by different I mean better).

Your brass is inconsistent if you are neck sizing fired brass from subs. It's probably minimal, but it's a factor. You really should fire-form your brass with supers, then neck size and load subs. Your subsonic load isn't enough bang to fully form the brass. It's a lot of work, but if you are really going for tight groups, it's one of the ways to remove inconsistency.
 
You really should fire-form your brass with supers, then neck size and load subs.

I've got some commercial supersonic stuff, I can fire that and then neck the brass... but I've been trimming it to length after the first resize. Skip the trim, or trim them after neck sizing after the first fire?

Is this a 300BLK thing or just subs in general?
 
I've got some commercial supersonic stuff, I can fire that and then neck the brass... but I've been trimming it to length after the first resize. Skip the trim, or trim them after neck sizing after the first fire?

Is this a 300BLK thing or just subs in general?

I would imagine subs in general (bottleneck anyway). It was brought to my attention on castboolits when I was figuring out my load and my brass was inconsistently sooty.


Trimming may be necessary after your first neck size depending on the brass. Probably not on subsequent firing as the brass doesn't stretch much. Sub loads for bolt guns are great in that instance. There's practically no wear as I understand it...
 
I haven't done any accuracy work in awhile now. I skip most of the precision extra steps/work as I primarily just like to bang steel and lob rounds 2-300yds and drop them in with ridiculous holdovers. Fun plinking that doesn't require extreme accuracy. It is definitely possible though. I had no trouble getting under 1" when I tried, but 2" was faster, easier, and just as much fun for my usual use. If I ever do get a chance to do some hunting with it, I'll work up more precision rounds again.
 
Thinking out loud here - maybe try annealing some cases and see if it improves neck tension?

Not a bolt gun owner myself but I helped a buddy load for his 300 BO, which has a tight chamber, and we had to outside neck turn a specific brand of converted mil cases to make them pass the Sheridan gauge. This gun has never had a problem chambering commercial 300BO cases.

Probably overkill in an AR15 but for my own prep I now neck turn all mil cases, anneal, ream primer crimps, deburr the flash hole and uniform the primer pockets.
 
Made up a batch with once fired brass all from the same batch and the neck tension was significantly more consistent than the older used brass. However, the accuracy results were about the same, 2=3" 5-shot groups @100. That sucks.

I brought out a known good rifle with a known good load in 308, and was putting out 5-round sub-MOA groups after the first 10 rounds (once I remembered how to drive the rifle) without drama. So I can still sorta shoot, if not as well as before. But still better than I'm seeing with the Ruger and my subsonics.

Am I expecting too much out of subsonics?

The first little trials with the 110gr VMAX supersonics looked pretty good to me and that was with very little experience with the rifle. I guess I can go back and try that again, see if the accuracy is still there with supers or if it was a fluke.
 
If you think the trigger nut is the problem, why not put the rifle into a mechanical rest? Wouldn't that eliminate (or minimize) the human element effect on accuracy?
 
.....ive been down this road. With heavy subsonics you had to keep your velocity as high as you could. 1050 -1090 fps.... you could expect about one inch groups at 100 yards on average. Some would be a little over....some would be a little less. When i got below 1000 fps or so......my groups got huge, mostly vertical stringing.
 
If you think the trigger nut is the problem, why not put the rifle into a mechanical rest? Wouldn't that eliminate (or minimize) the human element effect on accuracy?

I've thought about it, but no one has a mechanical rest that I know. I could probably build some sort of contraption to hold the rifle.... hmm.... we need some snow days so I can fiddle in the shop.
 
@Sas quatch gave me some magic bullets so load up, swears they'll be sub-MOA and regrow hair. Let's hope at least one of those things is true.

Now that I think about it, he's waiting for me to sell him this rifle... so maybe he gave me the worst bullets to load so I'll lose faith and sell? Hmm....
 
They're amazing. And... unobtainable once my supply runs out, unless @Butter has more of those coated 203s from last year.
 
I've been needing to develop a sub sonic load, but 9 is keeping really busy right now. My plan is to use Gallant coated 217s

They're amazing. And... unobtainable once my supply runs out, unless @Butter has more of those coated 203s from last year.
You sure it was me?
 
They're amazing. And... unobtainable once my supply runs out, unless @Butter has more of those coated 203s from last year.

I did some math using published subsonic semi-auto data to figure out how to reduce my 220gr bolt gun load data down to 203gr bullets and keep them subsonic; we'll see how well my guesses worked at the range.

If these turn out to be magic, I have a theory as to why. When I went to seat them, I just left the seater as it was to get the 220gr ELD bullets deep enough to load in the mag to see what that would get me. With these 203s, that makes them seat like this (the center round in this photo):

300blk_poly_205gr_seating_depth.jpg

However, when you try to chamber that in the rifle, it won't work, the bullet it touching the lands before the bolt closes. The round on the right is actually the max length you can have and still chamber it. With that depth the bullet is just a few thousands off the lands.

Perhaps the accuracy comes from that? Subsonic doesn't like the 'jump' to the rifling?

We'll know tomorrow.

I wanted to test some over the chrono in the yard today, but if I'm wrong on the load reduction and it goes supersonic, the wife would notice what I'm up to. She can hear everything.
 
Been side tracked on this project, but do have the next round of testing to do along with the last of those magic bullets from @Sas quatch.

I picked up some of the Missouri Bullet Company 215gr cast "300BLK" specific bullets from Midway. Have loaded up a few test batches but not fired them yet, but I do not have high hopes for these at all. Of the first 20 I pulled out of the box to load up, I found stuff like this:

IMG_6366.JPG

Is that for shooting around corners to the right? or is it a left handed bullet and I have it facing the wrong way? Anyway, this one was obviously not usable, and maybe 25% didn't look 'flat' across the nose. If they're visibly not concentric, how can they possibly be accurate down range at 100 yards? Guess we'll find out.

At least what I've been distracted with has been fun. Working on some loads for my 'accurate AR'. This is what I expect 5 round groups to look like @100.... but it's way easier with 77gr supersonic .22s.

IMG_6335.JPG
 
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