Cylinder or Cyl+Yoke Swaps: L & K Frame

[roo_ster]

Howdy:

QUESTION
Does a cylinder and/or cylinder+yoke swap require any additional adjustments or whatnot other than the swap itself?

OBJECTIVE
L and/or K frame .357mag/.38spl revolvers with with spare/swap-able cylinders for 9mm with moon clips.

BACKGROUND
I own both a 4" L-frame 686 .357mag and a 2" K-frame 64 .38spl., as well as other S&W revolvers. I have had J, K, L, and N frames disassembled down to frame+bbl and done some cleaning, spring-swapping, etc. Never dis-assembled past that point. Never have fiddled with timing.

Last year I shot some IDPA/sorta-IDPA with my kiddos. I shot my SW1911SC .45ACP and my kiddos Ruger MKII and MKIV .22LR. The matches were not explicitly "lost brass" but effectively they were as we could arrive early to set up, but could not stay late to tear down and pick up brass in the grass. I used to be THAT GUY who scrounged brass like an addict looking for a fix, so that cut to the quick.

IDPA and more vigorous rifle sessions have convinced me to start reloading again after a 15 year hiatus, but you can't reload what you can't recover. I figure 9x19mm in moon clips is cheap to buy retail loaded if necessary, cheaper to reload (bullet & powder) and all the moon-clip wheel-gun guys in IDPA get to pick up their moon-clips+empties after each stage, just like magazines from semi-autos.

I have seen 686 cylinders for sale for $100 or less. And I can send it off to get the cylinder altered to accept 9mm with moon clips. I can swap clyinders. Only question is if it requires more fiddling to run properly.

Thanks for any insight.

 

[Protocall_Design]

Every gun and cylinder is slightly different. Some may be a drop in trade, many will require a small amount to a lot of fitting.

 

[dfariswheel]

Cylinders are not drop in parts even today.

To install a cylinder requires that the ejector be fitted to the cylinder.
Then the assembly is fitted to the frame.
This requires the ejector face be long enough that it can be machined to establish proper head space.
Since a used ejector and cylinder have already been fitted to a different frame, the assembly may be too short to allow machining it to fit a different frame.
Ejectors cannot be stretched to fit. Either the ejector fitted to the cylinder is long enough or it's useless.

Once headspace is set, then the assembly has to be adjusted for....
End shake.
Barrel-chamber alignment on all chambers.
Barrel-cylinder gap.
And timing.

Cylinder installation is a major pistolsmithing job.
Just because a cylinder will snap into the frame is no indication that it really fits or is even safe to fire.

 

[Murdock]

This conversion worked well for me with a J frame M60-4. Found a 60-4 cylinder and yoke on ebay for a reasonable amount, and was gratified to have it snap right in with no extra fitting or timing. I had timed two N-frames with replacment cylinders in the past with minimal difficulty, so was prepared to do it for this gun, but was very happy that I didn't have to bother. I wonder if this is because CNC machining of more modern guns minimizes the need for as much hand fitting.

Sent the second cylinder to TK Custom for milling to accept 9mm. I could have simply had the cylinder that came with the gun milled, but did not want to degrade the resale value of the M60.

You are aware that to have the cylinder milled for 9mm still allows you to use .357 and .38 Spl as prior to the alteration, aren't you? Also, because the revolver chambers are deeper than the pistol chambers, my gun also accepts .38 Super and .380 ACP in addition to 9x19mm. Happy, happy.

 

[roo_ster]

Well, not the answer I wanted, but that sure beats gong in blind. I suppose I need a Plan B.