649 trigger stacking

sunnyd

sunnyd

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I recently acquired a very nice 649 no dash. Been on my wish list for a long time. The gun is in like new condition with a very low round count. It came with the usual j frame stiff trigger but with a very obvious stacking point in the beginning of the trigger pull in da. I disassembled and cleaned and lubed the internals. It was pretty dry inside and this helped smooth the trigger pull quite a bit, but the stacking is still there. When I pull the trigger there is a very obvious stacking point in the very start of the trigger pull. Once I get past this point the rest of the trigger pull is fine. If I pull the trigger really fast the momentum helps carry past the stacking point somewhat, but it is still noticeable. If I thumb cock the hammer, the stacking is not there when pulling the hammer back, so I assume the problem lies in the trigger. This gun is very accurate, but the stacking makes it difficult to stay on target. Before I start into the piece by piece analysis of the internals, I thought I would ask If any of you guys have dealt with this issue before, and could guide me to a specific part to check first. Thanks
 
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They say, "Fools rush in . . . " so take this suggestion with a grain of salt, please.

When first received, two of my later model J-frames (642-1 & 638-2) each had a noticeable "catch or hitch" just as the trigger was pulled. It annoyed me to the point that I lightly smoothed the very forward end of the MIM trigger with 1000 grit wet-or-dry sandpaper. Both triggers smoothed out nicely.

This worked for me. All of my J-frames are now smooth feeling from the very beginning to the end of the trigger pull.

However, I am NOT a gunsmith, so you may wish to wait for more qualified members to comment.

Best of luck, sir!
 
Very difficult to ascertain without the 649 in hand; the start of the trigger pull initiates a reaction literally throughout the entire action -- multiple moving parts, any of which if slightly gummed, burred or out of true could account for your hitch.

Suggest a qualified S&W revolversmith inspect, or -- if you know what you're doing -- you go ahead and tear it down and look it over.
 
It has been my experience that the increased pressure that you describe is influenced by the bottom cut angle of the sear. If the top rear of the trigger engages the sear in a relationship that slightly binds, you are going to feel a greater force on the trigger. After this "relationship" progresses, the influence of the static angle is minimized. Re-cutting the sear angle is critical, since too much material removed will produce a "stub" and that is unacceptable.
 
The sear angle is probably not fitted correctly. If you smooth it slightly with a stone and slightly curl the front edge it will most likely go away.
 
I have the same issue with my 929. The action was rough when I first got it, figured it just needed an action job.

There's a tooth/nipple on the front of the trigger where it contacts the cylinder lock. It's basically a heavy pull until you get over that cylinder lock then the pull is light and smooth. The issue I have with it is that it requires some force to get past that part and since you're applying more force than normally would be required, once you get through it causes the cylinder to jump quickly to the next round before the I'm even halfway through the pull.

I'm afraid to mess with this part since it's barely grabbing the cylinder lock as it is.
 
The trigger lug has been improperly adjusted (or possibly worn) so that the cylinder stop is not dropping from the cylinder cut before the hand rotates the cylinder. This is a delicate fit and one or more parts may need replacement and fitting.
 
Checked the timing of the hand and the trigger/cylinder stop. The stop drops before the hand starts it's upward stroke.

I believe the fast rotation of the cylinder is just due to there being such a steep amount of initial pull required that it's hard to maintain trigger control. Once I get past that rough spot, it lightens, then I try to maintain a slow pull again but it already caused the hand to bump the cylinder star and push it ahead of my pull.

If I pull the trigger super slowly with my thumb (for more control/strength/ease) I can control the pull more and it does have smooth hand operation of the cylinder. Maybe my trigger fingers weak...
 
It is really hard to diagnose your problem without the gun in hand. Your description of a steep initial pull indicates a problem that a competent armorer/gunsmith could remedy. Hope that you can get to the problem.
 
It looks like the hammer sear was uneven or had a burr where the trigger comes into contact with it. I sanded it down and rounded the bottom of the hammer sear so the trigger wouldn't catch a corner. Smooth now. Hammer drops just a hair after the cylinder locks up.
 
Thx for the input guys. I worked on the sear cut angle as suggested. Found it to be rough and polished it up. The action smoothed up quite a bit.
 
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