Double action characteristics - M15 S&W

[SPR1]

I picked up a new in box 20 year old M15 (S&W Heritage series with Turnbull color case hardened frame). The double action pretty much sucked out of the box.... Yes, I am a heathen and I am shooting it..... When I took the factory grips off to wipe it down I discovered some light rust. That helped me rationalize shooting it.

I slicked up a few burrs inside, put a 14 pound rebound spring and a different factory mainspring in it. This work has dramatically improved the trigger pull. As has firing and dry firing it about a thousand times.

But, since new, the final stacking portion of the pull, where you could stage it, is much more of a creepy, hard, increase in pull than any other Smith I have had. I am wondering if this could be insufficient clearance between the DA sear nose and the trigger?

Thoughts?

[Carmoney]

Sounds like it's knuckling. Usually that's from not enough arch in the mainspring, in conjunction with a strain screw that is too short, or has backed out.

[FWSixgunner]

Stacking & staging? You sure that's not a Ruger?

The absence of stacking is what I love about S&Ws, or Colts with leaf mainsprings. I'm no engineer, but I don't believe it's possible to eliminate stacking with a coil spring. It's resistance increases with compression.

I don't believe in staging for the very reason I like DAs: shooting rapidly, I cannot sneak up on a 5+ lb trigger that travels maybe 1/8" while gripping tightly to control recoil. Staging defeats the whole purpose and causes me to get "chicken-finger".

I can perform what Jeff Cooper described as "the nudge" with my old Hi Standard Supermatic Citation, but that's a .22 with a sub-2 pound trigger and no perceptible over-travel.

[Carmoney]

FWS, you show me a stock Colt DA revolver (leaf spring or coil) that doesn't stack, and I'll show you a whore that ain't had the clap.

A factory Python or Dick Special will stack every bit as bad as a GP-100 or Security-Six. There are a few good revo-smiths who know how to get rid of the well-known Colt stacking problem. I don't know how they do it, but I believe it has something to do with re-configuring the bends of the mainspring.

More trouble than it's worth.....although I guess if you like really nice polishing and bluing, older Colts are where it's at.

[SPR1]

I did not say I shot it using a staging method, it is just a way to describe where in the pull the problem exists. The weight just increase more and the pull is creepier there than I am used to experiencing. If you gave it to the average Joe, he might not even feel it.

In the cycle of operation, the cylinder carries up, locks, and then the pull gets creepy.

I put another factory Smith mainspring in it and the pull has the same characteristics, just at a lower total weight.

On another forum, a guy suggested the width of the hand and it dragging past carry up. Thoughts on that?

[FWSixgunner]

FWS, you show me a stock Colt DA revolver (leaf spring or coil) that doesn't stack, and I'll show you a whore that ain't had the clap.

OK, I'll confess to a lack of experience with Colt's. Mine is limited to an original Trooper, which is quite smooth.

[Tom E]

the cylinder carries up, locks, and then the pull gets creepy.

That's how it feels when the hand is slightly too thick.

[SPR1]

What is the best way to fix it? Thanks