.38 vs. 9mm?

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jfanatic

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Hey All! So I grabbed a neat little SW 642 from a forum member yesterday. As these will and can do over time, the clear coat and finish were beat to hell and rough - a diamond in the rough perhaps. Anyway, I tore it all down, stripped it down, polished, waxed it and installed a titanium cylinder I had laying around - but I digress. I'm sort of thinking about having the titanium cylinder or a steel cylinder reamed to 9mm. Any advantages, disadvantages? Ballistics, ammo availability, etc, etc, etc............. Just trying to decide if converting this to 9mm makes any sense - not that our hobby intrinsically makes sense. Also, if it does happen to make sense, any body have a recommendation for a smith that will do it?

Thanks in advance!!!642 prod.jpg
 
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Just from ammo availability perspective 9mm is still cheaper and easier to find.
From what I have found at some LGS's .38 is $1 a round if you can find it. 9mm between .6-.8 a round

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Unless there is a functional problem.......leave it alone.

Ballistics.......not a big difference between 38 special and 9mm luger. 9mm is cheaper and usually more available, but not a big deal. Things will settle down and 38 special will be more available and cheaper than current prices. If you reload.......the price difference between 38 special and 9mm is almost nothing.
 
You wouldn’t have to ream the cylinder. You would have to have it machined to accept moon clips since the 9mm is a rimless case. The 9mm bullet is a few thousandths smaller than 38 so accuracy might be terrible. Spend the money on a cheap reloading outfit and load your own 38’s. Even with the high price of components today you can still load for less than .25/round
 
frakncylons said:
Another note...

Too light and there will be bullet pull in 9mm. The LCR already exhibits this.

It may not be enough to lock it up but it would always be in the back of my mind.
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That's why I went with the LCR in 357. That whole bullet crimp shift thing.... yea, I know it doesn't happen with every round and the quality defensive stuff was shown to be immune to it in all real scenarios... but... it's in the back of my mind enough to go with the retro chambering.

As to 9mm vs. 38, my testing shows that if you take a G43 with the 147gr HST load as your baseline, my LCR running Critical Defense +P .38 special gives you only 58% of the energy of that 9mm 147gr out of a similar barrel length, and if you go full house 357 Critical Defense (which is damn hard to shoot well out of an LCR) you're only at 122% of that 147gr 9mm. You have to figure the 9mm LCR is somewhere between those two, and the 38 +p is the loser in all ways. Make the barrel longer and the 357 kicks butt, but we're not talking long barrels here, we're talking snubbies and however they measure semi-auto barrels that include the chamber.
 
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My experience with a 442 is that it’s not so much fun to shoot a lot. Back in ”normal times”, I might have shot several boxes thru other guns (K frame or a semi) but certainly less than a box (10 cylinders full) thru the J frame during one range session. I’d only fire the 442 enough to verify I could defend myself in case the broad side of a barn attacked me.

For that reason, spending money to make the gun shoot cheaper ammo doesn’t make a lot of sense to me.
 
The only way I would go with 9mm is if, as mentioned, it is set up for full moon clips for faster reloading. Otherwise, run the 135gr Gold Dot loads for defense or warm full wadcutters. And I would shoot the crap out of it with wadcutters anyway.
 
I think the other outfit that does moonclip conversions is tkcustoms.

I wanted to be able to shoot 45acp out of a Taurus 450ti but they won't work on Tauri.
 
Jeppo said:
My experience with a 442 is that it’s not so much fun to shoot a lot. Back in ”normal times”, I might have shot several boxes thru other guns (K frame or a semi) but certainly less than a box (10 cylinders full) thru the J frame during one range session. I’d only fire the 442 enough to verify I could defend myself in case the broad side of a barn attacked me.

For that reason, spending money to make the gun shoot cheaper ammo doesn’t make a lot of sense to me.
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I am a tolerable pistol shot, but I was horrific with a little J frame. I shelved mine.


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I thought about the same thing. TK customs does the work for $350, and they caution to only use standard pressure ammo or expect stuck cases. My experience with moonclips in j frames was with a PC 642, and finding the right brass to hold the rounds firmly in the clip was a PITA. Maybe 9mm would be different. For my money I just stick with Buffalo Bore’s 150gr standard pressure wadcutter in snubbies. I’ve come to believe, from research and extensive convos with men who‘ve had many more years carrying them than myself, penetration is the the most important factor when employing such a short barreled gun. YMMV. You could always go down and try some of @BatteryOaksBilly HELL rounds (230gr wadcutter under a ton of something hot) that he and @Etruett are cooking up. A cylinder full of those through a 340PD is an enlightening experience…after sensation returns to your hand in a half hour or so.
 
tbafile said:
I thought about the same thing. TK customs does the work for $350, and they caution to only use standard pressure ammo or expect stuck cases. My experience with moonclips in j frames was with a PC 642, and finding the right brass to hold the rounds firmly in the clip was a PITA. Maybe 9mm would be different. For my money I just stick with Buffalo Bore’s 150gr standard pressure wadcutter in snubbies. I’ve come to believe, from research and extensive convos with men who‘ve had many more years carrying them than myself, penetration is the the most important factor when employing such a short barreled gun. YMMV. You could always go down and try some of @BatteryOaksBilly HELL rounds (230gr wadcutter under a ton of something hot) that he and @Etruett are cooking up. A cylinder full of those through a 340PD is an enlightening experience…after sensation returns to your hand in a half hour or so.
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They are not designed to shoot many. Those are designed as man stoppers. In that situation, you wouldn’t notice the recoil
 
Etruett said:
You wouldn’t have to ream the cylinder. You would have to have it machined to accept moon clips since the 9mm is a rimless case. The 9mm bullet is a few thousandths smaller than 38 so accuracy might be terrible. Spend the money on a cheap reloading outfit and load your own 38’s. Even with the high price of components today you can still load for less than .25/round
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He would absolutely have to have the cylinder reamed, the 9x19mm is a tapered case while the .38 Special/.357 Magnum are straight walled. The 9mm is larger diameter towards the rear of the case than the .38/357 and won't go into the chamber without the chamber being reamed for the cartridge.

@jfanatic: S&W made a factory 940 back in the 90's. It was basically a 9mm 640, steel frame and cylinder, moon clips, 9mm chambers instead of .38 Special chambers. So far as I know S&W never offered a factory 9mm version of the Airweight. I suspect there is probably a reason for that. Is the 642 you got an older gun without the "magnum" frame or a newer one with the extra reinforcement around the cylinder stop? I definitely wouldn't have one of the older guns converted to 9mm. One of the newer ones might be doable but again, 9mm operates a significantly higher pressures than .38 Special/.38 Special +P (35,000 PSI for 9mm standard pressure, 17,500 PSI for .38 Special and 20,000 PSI for .38 Special +P). FWIW .357 Magnum is also 35,000 PSI. S&W doesn't offer their .357 J-frames with aluminum frames, the lightweight .357s have Scandium frames.

In normal times I would just tell you to buy a 9mm LCR or SP101 if you want to shoot 9mm in a revolver. It wouldn't be much more expensive (if any) than having a .38 Special revolver converted. However, I've been looking for a 9mm LCR for several months and haven't been able to find one at anything close to a reasonable price. I still probably wouldn't convert an Airweight to 9mm though I can see how that would be appealing if it was safe and reliable.

FWIW, Buffalo Bore is still shipping ammo and they have a bunch of .38 Special in stock. It is running about $1.50/round but in these crazy times standard .38 Special RNL is $1/round. That makes the Buffalo Bore seem a lot more reasonably priced.
 
Landric said:
He would absolutely have to have the cylinder reamed, the 9x19mm is a tapered case while the .38 Special/.357 Magnum are straight walled. The 9mm is larger diameter towards the rear of the case than the .38/357 and won't go into the chamber without the chamber being reamed for the cartridge.

@jfanatic: S&W made a factory 940 back in the 90's. It was basically a 9mm 640, steel frame and cylinder, moon clips, 9mm chambers instead of .38 Special chambers. So far as I know S&W never offered a factory 9mm version of the Airweight. I suspect there is probably a reason for that. Is the 642 you got an older gun without the "magnum" frame or a newer one with the extra reinforcement around the cylinder stop? I definitely wouldn't have one of the older guns converted to 9mm. One of the newer ones might be doable but again, 9mm operates a significantly higher pressures than .38 Special/.38 Special +P (35,000 PSI for 9mm standard pressure, 17,500 PSI for .38 Special and 20,000 PSI for .38 Special +P). FWIW .357 Magnum is also 35,000 PSI. S&W doesn't offer their .357 J-frames with aluminum frames, the lightweight .357s have Scandium frames.

In normal times I would just tell you to buy a 9mm LCR or SP101 if you want to shoot 9mm in a revolver. It wouldn't be much more expensive (if any) than having a .38 Special revolver converted. However, I've been looking for a 9mm LCR for several months and haven't been able to find one at anything close to a reasonable price. I still probably wouldn't convert an Airweight to 9mm though I can see how that would be appealing if it was safe and reliable.

FWIW, Buffalo Bore is still shipping ammo and they have a bunch of .38 Special in stock. It is running about $1.50/round but in these crazy times standard .38 Special RNL is $1/round. That makes the Buffalo Bore seem a lot more reasonably priced.
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Sorry, worded it wrong. Meant to say he wouldn’t only have to just ream, but cut for moon clips as well. there have been some guns designed for 380 and 9mm without moon clips but from what ive heard, reliability has not been perfect. Other than possibly buying ammo a little cheaper, I don’t see the change over being practical. After all the work, accuracy from a 9mm bullet in s 38 barrel is probably not going to be as good either. I’ve shot a good many 9mm bullets in .38 barrels playing around with reloads and never had any success. Spend the money on reloading equipment and eventually you will come out way ahead.
 
jfanatic said:
Just trying to decide if converting this to 9mm makes any sense -
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Not to me, and I've owned two J frame sized 9mm. First was a Ruger SP101, next was a S&W 940-1. I chronographed lots of 9mm and did side by side comparisons with my J frame .38 Specials, and saw no numerical advantage to the 9mm. This is probably why the 9mm Ruger and S&W did not sell well, and have not been re-introduced. Somewhere I still have my 9mm velocity numbers from the short barrels, and they were not impressive..

Also you have the pressure issue for the 642, which is just not built for 9mm levels If trying a conversion of that sort your would be better to start with a 640, which S&W initially advertised as "tested with +P+".

Another problem with the SP101 which would also give you problems with a 642 is they did not recalibrate the fixed sights for the different caliber, i.e. the 9mm SP101 had the same factory sight heights as the .38 Special version, which made the POI incorrect.
 
Please, don't do this.....I have shot a LOT of 9mm bullets in .38 cases. Fun but they don't shoot for beans as far as accuracy is concerned.
 
The 38sp with wadcutter loads has proven itself to surpass equally short barrel 9mm hp in the published studies. A 2" barrel 9 doesn't gives up too much velocity to expand those type bullets.
 
S&W used to make a 9mm J frame, the 940. I would personally just try and find one of those. Cool little gun.85976656_1_x.jpg
 
VolleyFire said:
S&W used to make a 9mm J frame, the 940. I would personally just try and find one of those. Cool little gun.
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Near impossible to do. The 940 no dash had lots of problems, which they addressed with the 940-1. My dash one also had a few problems, plus it would not fit in kydex holsters like Fobus, due to the non-tapered barrel.
 
I managed to find a LCR 9mm recently. I took it to shoot a BUG match last weekend. It functioned perfectly, shot point of aim, and generally impressed me. As far as felt recoil it was more than a .38 Special in a .357 LCR but less than a .357 in a LCR. I was primarily shooting Winchester 124 grain NATO ammunition which is higher pressure than “normal” 9mm. I also shot 15 rounds of 147 grain Gold Dot G2 to verify point of impact and reliability since that is my carry ammo in my duty gun.

I don’t see a really good way to carry spare moon clips so I think as a primary gun the 9mm LCR wouldn’t be the best choice. However, as a backup to a 9mm pistol it makes sense. It will headspace and fire without the clip so in a really bad situation it could be reloaded with rounds from a magazine. Extraction would be an issue in theory but in practice a lot of stuff would have to go wrong to need to reload after firing 5 un-clipped rounds.

All in all, 9mm LCR is highly recommended.
 
DaveInCLT said:
It identifies as a .38, don't try to change it's nature.
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+1

Moon clips suck. Own and use them and you'll agree.

Your gun is a reliable factory .38. You can get speed loaders, speed strips (not much speed there...), reliable ammo and function.

Don't take your reliable factory .38 and frankengun it into a 9mm. The cost of the conversion isn't worth the price of the ammo you could be shooting out of it.

that is assuming it's reliable and you don't hate using moon clips (you could load singly)

Just shoot lightweight .38 and become the best shot you can with it as is.

for a defensive .38 a crimson trace laser is great as the sights on these guns are miniscule

just know the POA/POI changes with distance using them
 
Jeppo said:
My experience with a 442 is that it’s not so much fun to shoot a lot. Back in ”normal times”, I might have shot several boxes thru other guns (K frame or a semi) but certainly less than a box (10 cylinders full) thru the J frame during one range session. I’d only fire the 442 enough to verify I could defend myself in case the broad side of a barn attacked me.

For that reason, spending money to make the gun shoot cheaper ammo doesn’t make a lot of sense to me.
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9B30944F-2FFB-4945-BAEE-0BEBECF51E6B.jpeg
 
My 642 shoots very accurately out to 25yds even with it's tiny sights. My normal load is a 115gr cast penta hp on enough universal powder for 1000fps. It's not that bad recoil wise but will do the job if needed. I load them for less than 10 cents a piece. It matches anything any 9mm short barrel does and costs even less.
In practice, I run the same bullet and powder backed off to 850fps for drills. Don't really think I will notice a difference between them under stress
 
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I own and shoot lots of .38 - if you can find the Speer short bbl Gold Dot ammo or Buffalo Bore heavy +P you have a good setup in the J.

Not sure your specific model is rated for +P, my old Model 60 100% stainless is fine.

With modern ammo the .38 is underrated.
 
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