Light strikes on a 69

[drumminor2nd]

Hey, all. Got a used Model 69 4.25" a few months ago and finally got ammo for it. The trigger on it feels like it's been "gunsmithed" with a stupid light pull (about 7 pounds in double action, well under 2 pounds in single action). Slick as snot? Yes. But I had five light strikes on Magtech 44 special in 10 rounds, while I had about seven light strikes on Fiocchi Defense Dynamics 44 magnum (sending the cylinder all the way around three times to get them all to fire).

I put in an OEM mainspring and tightened it down all the way. Now I got three light strikes on the same Magtech 44 special in two cylinders. Only appears to light strike in double action. Unfortunately, I don't have any other ammo to test at the moment, as 44 special is pretty rare it seems.

Any thoughts on how I can improve the reliability further? Seriously about to sell this thing to a gun shop and make it someone else's problem...

 

[StakeOut]

Have you tried a longer after market firing pin?
Smith and Wesson (S&W) Firing Pin Replacement | TK Custom Store

 

[stang1911]

Make sure someone hasn't shorted the strain screw. Should measure .505" OAL and .380" under the head for a round butt.

 

[Protocall_Design]

The firing pin needs to be a minimum .495 long. A .505 + or - a little bit is a lot better. A short firing pin needs a lot harder hit to set off the primers.

You can weigh the mainspring tension on the hammer with a trigger pull gage by hooking the scale under the hammer, holding the trigger all the way back, and checking the weight just as the scale pulls up off the frame. For good reliability on Federal primers, you want around 36 - 40 oz. For Winchester primers, about 44 - 48 oz. For CCI primers, around 68 - 72 oz. I don't know what primers your ammo has, but hopefully this information will give some guidelines.

 

[drumminor2nd]

Make sure someone hasn't shorted the strain screw. Should measure .505" OAL and .380" under the head for a round butt.

It's coming in at about .470 OAL -- looks like the end of the rounded tip was filed slightly flat, and to add insult to injury it had backed out a bit. I already tightened it back up, and the double action is a bit over 8 pounds and the single action is hovering at a little over 2 1/2 pounds. I put some blue loc-tite on it, but I don't think a $3 screw is the end of the world.

Thanks!

 

[BLUEDOT37]

It's coming in at about .470 OAL -- looks like the end of the rounded tip was filed slightly flat...

That could make all the difference.

Sometimes they just get flattened from wear too.

If you can't readily find a replacement S&W strain screw you can also use an 8-32 x 1/2" set screw, commonly found at hardware stores, along with some low-strength Loc-Tite to set the tension.

It's worth checking the firing pin's length while you're at it as they are frequently a cause of FTF & easy to replace.
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[ironhead7544]

I fixed a number of "trigger jobs" over the years. Take a spent primer and remove the anvil. Put it over the tip of the strain screw and tighten it down.

I experimented with backing the strain screw out. I started to get misfires at 1/2 turn. Backed out 1/4 turn worked and did lighten the action. I would not do this on a self defense revolver.

 

[drumminor2nd]

I fixed a number of "trigger jobs" over the years. Take a spent primer and remove the anvil. Put it over the tip of the strain screw and tighten it down.

I love troubleshooting Bubba's handiwork, don't you?

Thank you, all. I'll get this thing going again and love it when it's done whether it wants me to or not, haha.

EDIT: Bought a new stock screw -- and it's noticeably longer. Now the trigger and hammer are a bit harder to pull, but still incredibly smooth. I think i've got it solved. Thanks again!