There is a gunsmith working out of Pinnacle High Performance who is rechambering .38 J-frames to 9mm. Once the conversion is done you can only shoot 9mm with moonclips. He claims to have done several conversions in the last year and he has many current orders. Does anyone know someone who had this conversion performed? If so what were your experiences after the conversion? I'm really interested in doing this but would like some references.
Rechamber J-frames to 9mm
- Thread starter Tejano
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DrDremel
Member
More likely the gunsmith would have a S&W 940 cylinder fitted to the 38. That said, having owned two S&W 940 revolvers, they both had extraction problems with many brands of ammo. I would pass on this conversion.
I've read about taking a 940 cylinder and fitting it on a 642 no dash. ( I think it's a thread on this forum) But this guy says he will machine the steel cylinder on any .38 J-frame to use moon clips then rechamber it to accept 9mm. I have also heard about the extraction problems with some 940s. Many are still willing to pay a premium for 940s and work out the kinks.
Hey tekarra, I guess we usually hear about problems and not from the satisfied customers. But I have read alot of threads on THR that have solved issues or at least brought enlightment. I'm hoping to hear from anyone who has had this or other simular conversions done. I too, would love to have 15 oz. 942 J-frame.
deadin
Member
I don't think that .002" is going to make much of a difference in a 2" snubbie. Besides, the fixed sights are going to be off anyway because of the difference in bullet weights.
Brian Williams
Moderator Emeritus
in my conversations with Mark Hartshorn of Pinnacle he has told me about doing a number of reaming conversions of either a 38special or 357mag cylinder for J frames, there is a problem that firing 38 special or 357s will cause bulges in the case and potentially splits. Also the jump of the bullet from the short case thru the existing chamber of the 38/357 causes some inaccuracy.
He has done both 38/357 to 9mm and 38/357 to 38 super.
I had Mark fit a 940 cylinder to my 642 (it also fits my 60-4) and it makes for a great carry gun. I shoot my own reloads for practice so I do not blow up my non +p 642 with the high pressure 9mms.
Fitting a 940 cylinder is the best way, but the reaming method makes for a great "nose-picking distance" gun.
Mark said that most guys he has done this for want the gun for "nose-picking" distance shots or GOMA. Get Off My Arse.
My 38 barrel works fine with all of the 9mm bullets I have shot out of it.
He has done both 38/357 to 9mm and 38/357 to 38 super.
I had Mark fit a 940 cylinder to my 642 (it also fits my 60-4) and it makes for a great carry gun. I shoot my own reloads for practice so I do not blow up my non +p 642 with the high pressure 9mms.
Fitting a 940 cylinder is the best way, but the reaming method makes for a great "nose-picking distance" gun.
Mark said that most guys he has done this for want the gun for "nose-picking" distance shots or GOMA. Get Off My Arse.
My 38 barrel works fine with all of the 9mm bullets I have shot out of it.
Thanks for your reply Mr Williams. If I understand you correctly, once you ream a .38 cylinder to accept 9mm, there is no going back to .38 because the .38 case will blow up. Accuracy in the converted J-frame will suffer greatly due to the short 9mm case and the long .38 chamber. Using a 9mm cylinder is the way to go but can one use any version .38+P J-frame?
earplug
Member
Don't own one or want one.
Have thought about getting one of my four J Frames converted, then thought about any real advantage. None if you don't already carry or own A 9MM.
Back up reloads would be faster with the moonclips, but they would not pocket carry as easy as a speed strip. Who really needs A fast reload?
The hassle of the moon clip in practice would make me practice less.
While lots of hot 9MM loads are available, the street proven 158 grain SWCHP hits to point of aim. And I suspect is nicer to practice with.
Have thought about getting one of my four J Frames converted, then thought about any real advantage. None if you don't already carry or own A 9MM.
Back up reloads would be faster with the moonclips, but they would not pocket carry as easy as a speed strip. Who really needs A fast reload?
The hassle of the moon clip in practice would make me practice less.
While lots of hot 9MM loads are available, the street proven 158 grain SWCHP hits to point of aim. And I suspect is nicer to practice with.
Brian Williams
Moderator Emeritus
Yes there is no going back with out bulged cases and potentially split cases, notice I said potentially split.
Mark said there is a reduction in accuracy but not greatly reduced. Shooting quickly one can easily do minute of paper plate at 10 yards. It does not automatically turn into a shotgun pattern.
Mark said there is a reduction in accuracy but not greatly reduced. Shooting quickly one can easily do minute of paper plate at 10 yards. It does not automatically turn into a shotgun pattern.
Vern Humphrey
Member
The question I have is why not load hot .38 Specials? A .38 Special loaded to the same pressure as a 9mm will perform like a 9mm.
tulsamal
Member
That might be true if you were willing to carry "hot reloads" in your CCW gun. Many are not. They want to be able to use factory loads. Can't really argue with the fact that there is a heck of a lot more premium self defense ammo in 9mm than in .38 Special.
Now if the choice is between .357 Magnum and 9mm, then the only thing I can think of is cheaper practice ammo. But are you going to shoot it enough to save the money that you spent on the conversion?!
Gregg
Vern Humphrey
Member
I don't want to start a "reloads for self-defense" thread, but a .38 Special is a better choice at the same pressure levels than a 9mm in a revolver,
Couple years ago my friends and I chronographed several different 9mm, 38 special +P and 357 mag ammo fired through various 2" revolvers. I don't have the notes with me here at work but I believe we used:
For 9mm
S&W "J" frame with 2" barrel
Ruger SP101 with 2 1/4" barrel
Taurus 85 with 2" barrel
38 Special +P
S&W "J" frame with 2" barrel
S&W "K" frame with2" barrel
Ruger SP101 with 2 1/4" barrel
Taurus 85 with 2" barrel
357 Magnum
S&W "J" frame with 2" barrel
Ruger SP101 with 2 1/4" barrel
What was very surprising was that standard 9mm self defense ammo was closer to 357 mag performance than to 38 +P. In most cases 9mm +P ammo was about equal to 357 magnum performance from these short barrel revolvers.
Two loads I do remember was the Cor-Bon 9mm 115gr JHP +P which hit 1,310fps from the Ruger and 1,270 fps from the S&W. The legendary Federal 125gr JHP hit 1,300 fps from the Ruger and 1,250 fps from the S&W.
For 9mm
S&W "J" frame with 2" barrel
Ruger SP101 with 2 1/4" barrel
Taurus 85 with 2" barrel
38 Special +P
S&W "J" frame with 2" barrel
S&W "K" frame with2" barrel
Ruger SP101 with 2 1/4" barrel
Taurus 85 with 2" barrel
357 Magnum
S&W "J" frame with 2" barrel
Ruger SP101 with 2 1/4" barrel
What was very surprising was that standard 9mm self defense ammo was closer to 357 mag performance than to 38 +P. In most cases 9mm +P ammo was about equal to 357 magnum performance from these short barrel revolvers.
Two loads I do remember was the Cor-Bon 9mm 115gr JHP +P which hit 1,310fps from the Ruger and 1,270 fps from the S&W. The legendary Federal 125gr JHP hit 1,300 fps from the Ruger and 1,250 fps from the S&W.
deadin
Member
All with the same weight/configuration bullet?
Yes and no.
We compared
9mm (and +P) - 115gr
38 Special +P - 110gr
357 Mag - 110gr
then
9mm (and +P) - 124gr, 125gr and 127gr
38 Special +P - 125gr
357 Mag - 125 gr
finally
9mm (and +P) - 147gr
38 Special +P - 158gr
357 Mag - 145gr and 158 gr
All bullets were JHP or SJHP.
Not identical but we thought it was close enough.
We compared
9mm (and +P) - 115gr
38 Special +P - 110gr
357 Mag - 110gr
then
9mm (and +P) - 124gr, 125gr and 127gr
38 Special +P - 125gr
357 Mag - 125 gr
finally
9mm (and +P) - 147gr
38 Special +P - 158gr
357 Mag - 145gr and 158 gr
All bullets were JHP or SJHP.
Not identical but we thought it was close enough.
For what the conversion would cost plus the donor gun I'd think you could find an actual 940 out there. I'd like one but as I already have a 2 1/4" 9mm SP-101 it's pretty far down on my priority list. I'd sure like to see them produced again.
tulsamal
Member
Well, yeah, but doesn't that kind of turn it into an apples versus oranges kind of thing? The 9mm standard pressure load is much higher pressure than the standard pressure .38 Special. That's just the nature of the beast. Hotter than +P .38 Special as well. Sure you can load .38 Special even hotter and load 9mm weaker so that they meet in the middle but what's the point of that? The SAAMI standard for 9mm is for modern high intensity loadings. The .38 Special SAAMI standard has to accommodate a whole bunch of older guns that wouldn't be happy with higher pressure.
And that's without even getting into 9mm +P or +P+. Then you are moving right into .357 Magnum territory.
G
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