Interesting malfunctioning 625

[Tanners Owner]

I recently installed a new mainspring and TRS from Wilson combat on my 625-8. I tested it with factory and my reloads, worked great.

Recently I began to have a few light primer strikes (1-3 per match )on my reloads & concluded it was high primers. Last match I had ~40% misfires with some rounds with no primer indentations.

Initially I believed 2 causes might be the issue-
1- the VZ grips I used employ pins to better secure the grip that may interfere with free movement of mainspring and hammer

2 -a faulty/ broken firing pin

After the match, I swapped grips ( houge rubber) & confirmed the firing pin is good.

Went to the range today & am having same intermittent problems with both reloads & factory ammo. Am now thinking I have a TRS problem; possibly a timing issue or a problem with the transfer bar. I don’t think it has anything to do with the moon clips, I have no resistance when pulling the trigger and rotating the cylinder.

I plan on swapping the springs back to factory and running it on Weds to see if that solved the problem.

Any other thoughts, recommendations?

How does one confirm timing is good?

Thanks in advance

 

[Richard Simmons]

How about reinstalling the factory springs and see if it helps.

 

[elpac3]

I would have to guess it is a weak mainspring

 

[Tanners Owner]

That is the plan, but would the mainspring get weaker only after 500 rds?

 

[series guy]

I have found that especially on round butt guns that the factory strain screw is not long enough to use with aftermarket main springs. I use setscrews from McMaster Carr and adjust them for 100% ignition.

 

[Heinz]

If you have an improperly tempered main spring, it can rapidly weaken. Basically it is getting bent a bit each time you cock it. It will keep getting worse because the elasticity of the spring is inadequate. I am not saying that is the problem, but it has the same symptoms.

 

[Shrek Of The Arctic]

I've got very little to contribute that hasn't already been stated. I will add that I've personally had hammer springs soften out within 1K rounds, but I would expect you would feel that happening. I had been saying "Gee! This gun is really breaking in well with a smooth and light action!" when I found my hammer spring worn. It happened again recently when I realized the strain screw I hadn't bothered to loctite had backed out a turn and a half or so.

I have found the Wilson Combat springs to be a bit stouter with the strain screw all the way in as compared to Wolfe or factory and offer a bit more adjustment on the high "I wanna pop every crummy CCI primer I can find" end.

If it were my gun, I think I'd add a Power Custom extended firing pin. Between that, a spring, and a strain screw I'd expect it to be running correctly again. I realize it's a fairly unsophisticated "shotgun" kinda method, but all the parts are inexpensive, wear parts, and easy to install anyways.

Another thing I might would consider would be the primers themselves. I dunno how y'all are doin', but I'm havin' to beg and borrow for every darn primer I get these days. inconsistent brands, friends moving outta state, garage sales, etc. I have had some boxes of primers that weren't super reliable. Maybe stored poorly, handled with greasy pizza hands or whatever.

Timing would seem a remote possibility. Not that bad timing can't throw the firing pin off that far theoretically, but usually we're gettin' on the trigger hard enough to spin the cylinder into lock up, unless it's really sticky and outta time. It's not hard for a revolver to go outta time and not realize it for awhile.

To check the timing, I tend to very, very slowly and gently squeeze the trigger with the cylinder barely making contact with my finger tips. Just enough that it's not advancing from momentum basically. You're waiting for the cylinder to lock up before the hammer falls. To check the single action, it's the same thing, except your slowly pulling the hammer back. If I were a bettin' man, I'd say that is unlikely to be your issue, but then again, I'm just a far flung frozen redneck who makes every mistake possible and attempts to learn from it. A far cry from a Gin-Yoo-Wine Pistolsmith.

I look forward to reading how it shakes out for ya', and wish you the best of luck!

 

[Tanners Owner]

^^
I went with WC springs due to the feedback about them vs Wolfe, and just replaced the factory springs. Will go to the range on Weds & will report back then.

I do have an extended firing pin, C&S, when the factory firing pin broke , at a match years ago. I’ll look into the power custom version- thanks.

Fortunately I have a M10 & M15 to use at the sanctioned match next month if returning to factory springs doesn’t solve this.

Thanks for all who gave guidance.

 

[series guy]

The McMaster number for the setscrew is 95235A507. It has a nylon insert to prevent loosening.

 

[Tanners Owner]

As promised, results after I changed the TRS and mainspring back to the factory versions. One of the 6 rounds failed to fire in more times than not.

Upon closer inspection, the problem round has a firing pin indentation either on the edge of the primer or on the casing near the primer. This leads me to think it’s a timing or timing related problem.

Attached are the pics of 3 moonclips. Look at the round at 3 o’clock. This occurred w/ factory rounds too.

I don’t see anything wrong with the rear of the cylinder, but notice some minor peening on the cylinder bolt notches.

Thoughts?

 

[Nightowl]

It looks like the firing pin indentions are pretty deep, almost piercing one or two primers.

I have no clue what the problem could be, but I was taught that before seeking to repair a seeming problem, that one should make sure everything is clean and in spec, including carry up, endshake, yoke alignment, etc,

 

[Tanners Owner]

It looks like the firing pin indentions are pretty deep, almost piercing one or two primers.

Yup, saw same. Result of extended firing pin with factory springs. But did make the hits on the sides more noticeable

 

[growr]

Had a similar problem with the Wolf spring kit in my 625 JM, returned it back to factory springs.....problem is gone.

I won't have any firearm that is primer specific.

Randy

 

[Tanners Owner]

Shot it once more. This time I focused on the cylinder movement. 1st moonclip fired slowly had not issues. Next 2 moonclips while shooting faster had one round each not fire with similar firing pin indentations on the edge of the primer.

I did notice the cylinder over rotate in both cases, but only on the one chamber.. I can’t repeat this while dry firing.

I suspect timing, but am far from an expert. Any suggestions?

 

[Tanners Owner]

A friend who is a retired police armorer confirmed it’s a timing issue, specifically the cylinder stop and pawl.

Will update this as it matures

 

[tmd17]

The McMaster number for the setscrew is 95235A507. It has a nylon insert to prevent loosening.

Does this set screw work in other model S&W revolvers ?

 

[series guy]

Yes it does. Works in K, L, And N frames.

 

[Protocall_Design]

If the notches are peened, often there is a burr on both sides, though it will usually be bigger on the far side that the cylinder stops against. Even a small burr on the ramp side will bounce the stop down under rapid fire, allowing the cylinder to rotate past the notch. You will always get misfires if the firing pin hits far enough off center.

I would start with peening the burrs back down to where they came from. Do not file them off. You want that material to still be there. Use a wide, flat bottom steel punch for the burrs on the plain side. Use the side of a 5/16 diameter steel rod on the ramp side, as it conforms to the ramp size and shape. Doing this may solve the problem, and will tighten up the fit of the stop and notches. Revolver smithing is the art of adjusting that which is non adjustable.

 

[Tanners Owner]

If the notches are peened, often there is a burr on both sides, though it will usually be bigger on the far side that the cylinder stops against. Even a small burr on the ramp side will bounce the stop down under rapid fire, allowing the cylinder to rotate past the notch. You will always get misfires if the firing pin hits far enough off center.

I would start with peening the burrs back down to where they came from. Do not file them off. You want that material to still be there. Use a wide, flat bottom steel punch for the burrs on the plain side. Use the side of a 5/16 diameter steel rod on the ramp side, as it conforms to the ramp size and shape. Doing this may solve the problem, and will tighten up the fit of the stop and notches. Revolver smithing is the art of adjusting that which is non adjustable.

Appreciate the guidance, and what you say here makes good sense. However, I’m not that comfortable with doing the work myself & am sending it to a gunsmith my armored buddy recommended. Some things I’m comfortable working on, others not.

Will update as this matures & I really appreciate everyone who contributed