How safe is a S&W M34-1 rechambered to a .22Mag

tmon · June 13, 2013, 10:28 PM

How safe is a S&W M34-1 rechambered to a .22Mag?

Venom1956 · June 14, 2013, 01:17 AM

your guess is as good as ours?

If a good smith did it one would think it would be fine. But unless you are the one converting it you do not know what has or hasn't been done correctly or incorrectly. Its a bit of a wild card? Also I don't think S&W accepts re chambered guns for repairs but don't quote me on that.

Jim March · June 14, 2013, 02:16 AM

You know...worst case the frame was made for 38Spl levels of "boom" which are going to be more than 22Magnum. And even if the cylinder wasn't heat-treated to 357Magnum spec, you've got SO much meat around the chambers that I would be willing to call this an extremely safe conversion overall. It's not an "edgy" proposition and I don't think an engineering degree is needed to make that case.

I would look at the alignment issues with the normal "checkout" and if it's OK I wouldn't hesitate to shoot the snot out of it.

NOTE: I am assuming this is a six-shooter and not an eight-shooter or nine-shooter. If it was the latter originally as a .22LR then reaming it to 22Magnum might leave thin chamber walls. But in a six-shot J-frame? When we know that that frame and cylinder can handle six shots as a 32Magnum? The 22Mag isn't "edgy" at all in that situation.

carguychris · June 14, 2013, 11:14 AM

^^^ I fully agree with Jim, but I'm curious whether the particular gun is a pre-existing conversion, or if the OP is considering the conversion of a currently .22LR M34-1.

If it's the latter, and the gun is in decent cosmetic condition, I feel obligated to discourage the OP from considering this project. It will ruin the collector value of a revolver that has climbed in price by roughly 30-40% within the last 7-8 years.

S&W offered basically the same gun in .22WMR from the factory as the M51 with blue or nickel finish, or as the M651 in stainless. Although these are harder to find than a .22LR Smith, prices are roughly comparable in my experience.

PetahW · June 14, 2013, 01:18 PM

.

I'd be more concerned that the LR-positioned firing pin would give good/constant ignition with the little bit larger diameter rim of the .22WRM; and the barrel's bore/groove diameter being suitable/accurate as well.

.

Sevens · June 14, 2013, 03:37 PM

Quote:

I'd be more concerned that the LR-positioned firing pin would give good/constant ignition with the little bit larger diameter rim of the .22WRM; and the barrel's bore/groove diameter being suitable/accurate as well.

Great point. .22WMR seems to be built to a higher grade than bulk .22LR is, but both are relatively thin in the case head, and must be by design. Hit it in the WRONG place (yet still detonate it) and you've got gas leakage, and that is NO small problem.

To further discuss your second point about the bore/groove diamter-- it's been said that the Ruger Single Six Convertible's barrel is built to a jacketed .224" bullet spec, and "also" runs the ever so slightly smaller diameter heeled .22LR slug, and that accuracy -MAY- lack a bit when running .22LR in a platform designed around the .22 WMR.

I simply do not know if this is truth or internet rumor fodder, but it begs the question of the barrel's bore diameter in the Smith & Wesson Model 34. If the bore diameter is designed around a heeled, lead or copper-washed .22LR slug and not a true, jacketed .224" barrel, you'll have issues right there, specifically with regards to increased pressures.

Dangerous pressures? I wouldn't imagine so, but perhaps outside the design.

The project sounds like a Rube Goldberg at every turn. And when you consider the attractive Model 34-1, there's a very nice revolver that gets corrupted in the middle of it.

NoSecondBest · June 14, 2013, 04:44 PM

Quote:

To further discuss your second point about the bore/groove diamter-- it's been said that the Ruger Single Six Convertible's barrel is built to a jacketed .224" bullet spec, and "also" runs the ever so slightly smaller diameter heeled .22LR slug, and that accuracy -MAY- lack a bit when running .22LR in a platform designed around the .22 WMR.

I simply do not know if this is truth or internet rumor fodder, but it begs the question of the barrel's bore diameter in the Smith & Wesson Model 34. If the bore diameter is designed around a heeled, lead or copper-washed .22LR slug and not a true, jacketed .224" barrel, you'll have issues right there, specifically with regards to increased pressures.

Dangerous pressures? I wouldn't imagine so, but perhaps outside the design.

This subject is never ending. A few years ago a fellow who knew how to measure, undertook a detailed study of bore diameter and bullet diameter on the Ruger Single Six convertables. His results showed a very significant overlap of dimensions for each. Ruger did not make the convertable barrel any differently than they made the dedicated 22LR barrel. Also, a detailed study of bullet diameter showed a large overlap. I owned one of these guns in the early 90s and shot silhouette with it. I once shot a 77x80 at the IHMSA Internationals with it and if it was "barreled for 22mag" it didn't seem to know it. It also shot 22mag just about as good. He claimed that Ruger told him there was no statistically significant difference in bore or bullet diameter that would affect accuracy. I think he's right. He is also a top shooter. Also, back in the early 70's (if memory serves) S&W would make and fit an extra cylinder to your revolver so you could shoot both types of ammo out of the same gun. A friend of mine had one and it shot very well with both also.

newfrontier45 · June 14, 2013, 05:42 PM

I don't think there's an issue with this whatsoever. Whatever thousandth or two difference there 'may' be in bore size (don't forget the difference can be made up for in tolerance stacking) is negligible. Pressure for both cartridges are the same. The .22Mag is only very slightly larger in diameter.

Quote:

A few years ago a fellow who knew how to measure, undertook a detailed study of bore diameter and bullet diameter on the Ruger Single Six convertables.

Ruger has been using the same blanks for all their .22 Single Six barrels since 1968. I think this gets unfairly blamed for the accuracy issues in some guns. What we must remember is that Ruger cuts all six chambers at once and makes cylinders in batches. Very little actual fitting goes on. They were never meant to shoot like pre-war Colt's and S&W's.

tmon · June 14, 2013, 09:03 PM

I've found a M34-1 rechambered to a .22Mag for sale and I can't find a S&W 351PD to buy anywhere.

Venom1956 · June 14, 2013, 09:22 PM

I would wait to get the gun you want.

Compromise is something you do with your significant other not firearms.

Jim Watson · June 15, 2013, 06:56 AM

It is safe.
Maximum chamber pressure for .22 WRM is THE SAME as .22 LR, 24,000 psi.
I doubt the slightly tighter LR barrel is going to affect that much. A centerfire revolver maxes out in pressure before the bullet is all the way out of the cylinder and the rimfires are not likely different.

The WRM head diameter is .016" larger than LR. Will the .008" greater set-out to the rim affect ignition? What does Ruger do for convertibles?
I don't know.
But you should and you can find out. Insist on a testfire before you pay.

I once saw a Diamondback with extra cylinder rechambered to .22 WMR. A neat outfit and it did not stay on the shelf very long.

Old Stony · June 20, 2013, 07:09 PM

In the early days of Ruger single sixes, apparently they had some concerns about barrel diamater. They made the 22lr and then a dedicated 22 mag only version. Eventually they came out with the .22mag available with a fitted .22lr cylinder, and then on to the currently type of convertible as we know it today. I would guess they stayed with a slightly larger bore diamater in the current type of convertible. I have seen more than one conversion of different guns of the years from Lr to mag...including a pretty popular conversion of some of the Winchester pumps from 06's to 90's.
I doubt you will have any problems with yours...

June 13, 2013, 10:28 PM	#1
tmon Junior Member Join Date: June 13, 2013 Posts: 2	How safe is a S&W M34-1 rechambered to a .22Mag How safe is a S&W M34-1 rechambered to a .22Mag?

June 14, 2013, 02:16 AM	#3
Jim March Senior Member Join Date: February 14, 1999 Location: Pittsburg, CA, USA Posts: 7,417	You know...worst case the frame was made for 38Spl levels of "boom" which are going to be more than 22Magnum. And even if the cylinder wasn't heat-treated to 357Magnum spec, you've got SO much meat around the chambers that I would be willing to call this an extremely safe conversion overall. It's not an "edgy" proposition and I don't think an engineering degree is needed to make that case. I would look at the alignment issues with the normal "checkout" and if it's OK I wouldn't hesitate to shoot the snot out of it. NOTE: I am assuming this is a six-shooter and not an eight-shooter or nine-shooter. If it was the latter originally as a .22LR then reaming it to 22Magnum might leave thin chamber walls. But in a six-shot J-frame? When we know that that frame and cylinder can handle six shots as a 32Magnum? The 22Mag isn't "edgy" at all in that situation. __________________ Jim March

June 14, 2013, 01:17 AM	#2
Venom1956 Senior Member Join Date: October 4, 2008 Location: WI Posts: 3,656	your guess is as good as ours? If a good smith did it one would think it would be fine. But unless you are the one converting it you do not know what has or hasn't been done correctly or incorrectly. Its a bit of a wild card? Also I don't think S&W accepts re chambered guns for repairs but don't quote me on that.

June 14, 2013, 11:14 AM	#4
carguychris Senior Member Join Date: October 20, 2007 Location: Richardson, TX Posts: 7,523	^^^ I fully agree with Jim, but I'm curious whether the particular gun is a pre-existing conversion, or if the OP is considering the conversion of a currently .22LR M34-1. If it's the latter, and the gun is in decent cosmetic condition, I feel obligated to discourage the OP from considering this project. It will ruin the collector value of a revolver that has climbed in price by roughly 30-40% within the last 7-8 years. S&W offered basically the same gun in .22WMR from the factory as the M51 with blue or nickel finish, or as the M651 in stainless. Although these are harder to find than a .22LR Smith, prices are roughly comparable in my experience.

June 14, 2013, 01:18 PM	#5
PetahW Senior Member Join Date: September 19, 2008 Posts: 4,678	. I'd be more concerned that the LR-positioned firing pin would give good/constant ignition with the little bit larger diameter rim of the .22WRM; and the barrel's bore/groove diameter being suitable/accurate as well. .

June 14, 2013, 09:03 PM	#9
tmon Junior Member Join Date: June 13, 2013 Posts: 2	I've found a M34-1 rechambered to a .22Mag for sale and I can't find a S&W 351PD to buy anywhere.

June 14, 2013, 09:22 PM	#10
Venom1956 Senior Member Join Date: October 4, 2008 Location: WI Posts: 3,656	I would wait to get the gun you want. Compromise is something you do with your significant other not firearms.

June 15, 2013, 06:56 AM	#11
Jim Watson Senior Member Join Date: October 25, 2001 Location: Alabama Posts: 19,175	It is safe. Maximum chamber pressure for .22 WRM is THE SAME as .22 LR, 24,000 psi. I doubt the slightly tighter LR barrel is going to affect that much. A centerfire revolver maxes out in pressure before the bullet is all the way out of the cylinder and the rimfires are not likely different. The WRM head diameter is .016" larger than LR. Will the .008" greater set-out to the rim affect ignition? What does Ruger do for convertibles? I don't know. But you should and you can find out. Insist on a testfire before you pay. I once saw a Diamondback with extra cylinder rechambered to .22 WMR. A neat outfit and it did not stay on the shelf very long.

June 20, 2013, 07:09 PM	#12
Old Stony Senior Member Join Date: May 31, 2013 Location: East Texas Posts: 1,705	In the early days of Ruger single sixes, apparently they had some concerns about barrel diamater. They made the 22lr and then a dedicated 22 mag only version. Eventually they came out with the .22mag available with a fitted .22lr cylinder, and then on to the currently type of convertible as we know it today. I would guess they stayed with a slightly larger bore diamater in the current type of convertible. I have seen more than one conversion of different guns of the years from Lr to mag...including a pretty popular conversion of some of the Winchester pumps from 06's to 90's. I doubt you will have any problems with yours...