Thoughts on SW 625 problem - no primer strike on 1 cylinder..

[smsdba]

SW 625 - .45 ACP, moonclips, bought used from a friend.

First day out with it and hit this problem:

Consistently fails to strike the primer on one cylinder, and occasionally on the one just behind it, in double action. In single action, no problems. This has occurred with different ammo and across several steel moonclips.

Not a light hit...the primer is virtually untouched...and if I pull the trigger several times around, still won't strike the primer. If I rotate the cylinder to queue up the unfired round and cock it, boom single action. If I take the same moonclip out and rotate it in the cylinder, boom, the round is fired double action.

Using Fed 150 LP primers in my reloads.

Not seeing anything different with this cylinder visually and no appreciable run out seen while spinning the cylinder and viewing from the side. Crane is true, not bent and doesn't wobble.

Any thoughts or similar experiences would be appreciated.

I'm going to start with a local smith with a lot of experience. If he can't diagnose/correct....ship it to SW.

Thanks, smsdba

 

[Old Fuff]

Use a felt-tip marker and mark the back of the cases. Go around once, and examine the case heads for rub marks, and the unfired primer(s) for any sign of a hit. If there is no sign of a hit I suspect the cylinder isn't being locked on that particular chamber and it spins past far enough for the firing pin to miss the primer.

If that doesn't go anywhere, check the cylinder for end-shake. Using ordinary automotive feeler gages, push the cylinder backwards as far as you can, and measure the distance between the front of the cylinder to the back of the barrel (cylinder gap). Then repeat, but push the cylinder forward. Subtract this number from the first result, and the difference will be the approximate end-shake.

Fire double-action, but when you have a misfire see if you can turn the cylinder any direction with your fingers.

When you get some results come back, and we'll see what we can "figger" out.

 

[Iron bottom]

You probably already know this, but here it goes. A Smith .unless allowed to fully reset, will turn the cylinder without cocking and releasing the hammer. This can easily happen while speed shooting. This could explain why the pin does not hit the primer.

 

[Old Fuff]

Maybe, but usually what happens if the cylinder stop doesn't reset is that the cylinder locks up and won't turn. However if the stop has skipped a notch for some reason the pin will probably miss the primer, and the cylinder will still be free to turn. The question here is, "why just one chamber (or perhaps two) are effected?" That could indicate something is wrong with one or more of the cylinder's ratchet teeth or the hand.

Tis very hard sometimes to "figger" these things out over the Internet.

 

[smsdba]

Old Fuff/Iron Bottom....

Thanks and it appears your thoughts on timing were correct.

I put in snap caps and fired in 2B action. Everything is fine while pulling the trigger slowly. But when I speeded it up I noticed the bad cylinder was ending up in between, and also found primer strikes all over the face of the case, outside the primer circle. (photo attached)

In examining the cylinder's ratchet teeth, there are a few that looked rather chewed up. The one opposite the problem cylinder is photo attached.

I don't know how to evaluate the advancing hand. Am I looking at needing a new cylinder?

smsdba

 

[Old Fuff]

Well it doesn't look good...

If only this notch is bad it might be possible to adjust the ball on the cylinder stop (the part that comes up through the frame and into the cylinder's notch) so that it was a little higher and deeper into the notch, and then carefully peen some of the metal back to restore the notch. Otherwise yes, the cylinder would have to be replaced - at least for fast double-action shooting. If or when the cylinder is replaced the cylinder stop should be adjusted to be sure the ball is fully engaged in the notch. It looks to me like that isn't the case now.

In any event, the heavier the cylinder is - the worst example being a .38 Special or .357 Magnum N-frame - the more likely you will see this, but it happens on big-bore N-frame's too. The best way to lessen it is careful fitting of the lockwork, especially the cylinder stop.

It is less likely to happen on .38 Special or .357 Magnum K-frames, simply because the cylinder is lighter. But Jerry Miculek uses N-frame revolvers, and they apparently hold up. I think the reason must be the way the lockwork is fitted or adjusted.

 

[smsdba]

Thanks Old Fuff...

I just got off the phone with SW Support and it's going back for service.

They informed me that their lifetime warranty did not begin until 1982, so this 625-8 (1978) is not under warranty (regardless of first/second owner status).

Appreciate your expertise.

smsdba

 

[Old Fuff]

I just got off the phone with SW Support and it's going back for service.

This is likely a good move. But when you return the gun be sure to explain what kind of shooting you do with it, especially if that includes fast double-action work. The more they know about you're shooting habits the more likely it will be set up to perform like you want it too.

 

[gfen]

Had a S&W airweight M38 that I purchased used exhibit the exact same problem.

Since I had bought it two weeks before I found out about its "issue," I took it back to the store. They sent it to S&W for me and then S&W replaced the cylinder stop and spring and it worked like a champ since.