.38 Cylinder swap?

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DMK

New member
I've been toying with the idea of swapping cylinders in one of my British M&P .38 S&W project revolvers to convert it to .38 Special. I see three potential problems here:

.38 special is smaller by .002 than my barrel. However, Ruger sells a Blackhawk .38/9mm conversion which uses bullets with the same difference. 9mm works in it, doesn't it?

Cost. Numrich has replacement cyinders for about $50 and the lower cost of .38 Special would pay for the cylinder in no time. I'm refinishing it, so I'm taking it apart either way.

.38 special is a little hotter. I just can't see how this pistol couldn't take reasonable loads in that caliber. Most of these old M&Ps were made to shoot Special and I doubt that S&W would have gone through the extra cost of changing anything for the Brits except the barrel and cylinder.

Is there something else I'm missing here?
 
I'll start it, should be more to follow.

Lot of variation in actual bore diameters, yours might be tight or loose for the caliber. Slug it.

Rarely is a cylinder swap a drop in chore. Usually requires a bit of fiddling to get the timing right. Skill required.

Gun plenty strong enough for .38 Special.

Next ?

Sam
 
Strength is not a problem. This same gun was made in .38 Special by the millions as the M10. The only trouble would be the larger bore. Your gun might shoot fine, or might throw lead all over the place. Have you considered changing the barrel, too? I bought a Victory Model with a damaged barrel and picked up a used tube in good condition for $5 on ebay. You may not find one that cheap, but you might. I changed mine myself using the bench vise in the garage with two boards padding the jaws. Took about an hour with biggest grief coming when I had to drive barrel retaining pin back in. Fought that for at least 45 minutes. Rest of job took 15 minutes.
 
Thanks guys.

I'll do some more research on cylinder timing and barrel swap. That'll give me something to chew on for a while. Sounds like a fun project to me! :)
 
DMK: the cylinder has the be fitted to the crane and the frame so that:

1) End shake of the cylinder is .001 - .002". If the cylinder is set up "long", it will warp the crane when it is forced into the frame and also bind as it turns.

2) Cylinder - barrel gap is between .003" and .006". This is generally adjusted last by changing the set position of the barrel. Re-setting the barrel is not for ametuers as the frame can be easily cracked by over torqueing.

3) Alignment to the barrel when the cylinder is in lock up (check with a range rod).

4) Timing has to be correct so the cylinder/hand have to be set up properly.

I think you will find these are not trivial to do. A lot of new guns shipped these days are not even set up right.
 
In order for this to work properly you will have to swap the barrel as well

the dia of a 38 S&W runs .365 a whole lot more than the .357 of a 38 special. the 357 mag/9mm works becouse the dia are close .355 for the 9 and .357 for the magnum. If you change both barrel and cylinder for 38 special ones you will have a basic model 10. for about $200 you can buy any number of them. ($169 for Model 10 HB at a surplus dealer currently) so in the end its not really cost effective to do the conversion.(Barrel $50, cylinder $50, fitting of both $50. Now you have an additiona $150 in a gun worth about that much! Be much more in your favor if you left the gun as is and/or sold it for a model 10 in 38 special. These are nice guns in their origional caliber and can be a lort of fun. My advice (for whats its worth) is leave the old soldier alone and shoot it as is. JMHO
 
Thanks guys for taking the time to explain the details of this to me.

After considering what is involved with this, I'm going to just repair, refinish and enjoy them in the caliber they are.

Like the wise saying goes, "if it ain't broke, don't break it!"
 
bad idea cylinder swapping

DMK,
I have been trained properly to repair S&W revolvers. You shouldn't even be thiniking of such a conversion. First of all, the ratchet assembly is fit for the parent frame in which the cylinder is paired with. Second, you do not have the tools and know how to safely gauge inspect your revolver. The parts are simply not interchangable, but rather handfit to the individual revolver in question. You may end up with a binding or frozen cylinder and/or many hard spots in the rotation of the cylinder when different dimension (non compatable) parts do not function properly. Don't do it!
 
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