Old M&P sear

[madcratebuilder]

I have a old (1920ish) pre 10 M&P that a young man attempted to do a trigger job on....with a mill bastard. I don't have much experience with the long action, but I have replaced the hammer and have SA back but it's not picking up the sear soon enough in DA, the original is short. He may have ground on the trigger surfaces, not positive. This trigger job was done twenty years ago and it's has set since. I need a DA sear and maybe a trigger. If anyone has one please let me know.

 

[Old Fuff]

You may find a sear here - but you might have to buy the trigger assembly to get it.

www.e-gunparts.com

Now some good news!

While S&W changed the hammer in post-1948 short action revolvers, and used a different spring in the trigger to tension the hand, the newer triggers are backwards compatible. Therefore the more easily obtained model 10 (or any other K-frame trigger) will work fine. It is possible the new MIM K-frame triggers might work, but I haven’t tried them and don’t plan to.

Anyway the above listed source will also have triggers.

An additional thought. If you do buy a hammer, provide the seller with the serial number of your revolver. The pre-war M&P used a different hammer block then later ones.

 

[madcratebuilder]

Thanks Fuff, I have a post war pre 10 I can rob the trigger from and see if that is part of my problem.
OK, I hope I can describe this so you understand. I have a sear that may be long enough, but the top side, or short side, is cut at to much of an angle and allows it to pivot up to far. I thought about silver soldering some steel shim stock and file to get the needed angle, but I'm not sure if it well have a wear issue.
If I TIG material on it I'm pretty sure I would need to run it through some kasenit to surface harden. Then it turns into work.

Thanks again.

 

[Old Fuff]

I understand what you are saying...

I suggest that you check with Numrich at www.e-gunparts.com and see if they might have either a new sear (unlikely but possible) or a used but unaltered one. Also if they have or don't have a hammer assembly for a .38 Military & Police within the serial number range of the revolver you have. After you know what is or isn't available decide what direction to go.

 

[madcratebuilder]

I have a sear on the way from them. I need to get a few projects off the desk here so I can start on this Smith. Now that I know that I can use a short action trigger I think I well make some headway.
I'm trying not to put a lot of time in this, I'm helping this kid out only because he does want to keep the gun and it belonged to his great grand dad. I sure wish he would sell it to me.
Thanks again Fuff.

 

[Old Fuff]

You are indeed a gentleman, but if the kid is the one who used a mill bastard file be sure to LockTite the sideplate screws... :banghead:

 

[Jim K]

I think the confusion is that the part S&W calls the sear is usually called the hammer strut; it is part of the hammer, not part of the trigger.

I doubt you can get that old a part from Gun Parts, but good luck. As to welding, those thin sides usually won't stand up to welding. (Do NOT ask how I know.)

A gunsmith could make one, but not easily or cheaply. I hope you are lucky enough to get the right one from Gun Parts.

Jim

 

[Oyeboten]

Pics?

 

[madcratebuilder]

I bought a new old stock hammer off gunbroker. It was listed as a victory hammer and identical to the original.

When this gun came to me it had a catch in the DA pull. The trigger did not pick up the DA sear soon enough. If you helped the hammer past that, the rest of the DA pull was normal.

The SA notch was intermittent to find, when you did and pulled the trigger, the hammer caught the trigger and forced the trigger back as the hammer fell.
The new hammer cured the SA problem but still has the catch in DA pull, still not coming up on the DA sear soon enough. I need to try a known good trigger assemble.

As I said, it had been filed on many years ago and stored, things got a little rust and it's hard to tell just whats been filed on. I'm beginning to think the flat above the trigger sear has been altered. That is the area that lifts the DA sear.

I well get some photo's when I start on this again. Thanks to all.

 

[madcratebuilder]

double tap

 

[Jim K]

Falling off the SA notch is a common result of trying to lighten the SA trigger pull. Most hammer guns depend on the trigger finger reflexes to work right. Take a SAA revolver. If the trigger pull of the full cock is too light, the finger will not be putting on enough pressure to pull the trigger past the half cock and safety notches, and the hammer will batter itself and/or ruin the trigger.

On that gun the SA pull was lightened too much. The finger pressure required for release was not enough to make sure the hammer strut (sear) cleared the trigger. That was fixed.

Now, the second problem, the "catch". With the sideplate off and the mainspring removed, take a look at the trigger and hammer engagement. The trigger should push the sear upward, raising the hammer, to a point. Then the bottom cam on the trigger should catch the bottom of the hammer and continue the movement. At that point, the hammer strut should be free of contact with the trigger.

I think the "catch" is at that point where the direct trigger to hammer contact takes over. It could be that the person who messed up the hammer also messed around with the trigger, or that the new hammer also has problems. One thing to check is if, after the trigger takes over, the strut (sear) becomes free with no further contact. If the strut is too long, it can interfere with that transfer, then snap forward, causing a "catch".

(That little action beween the hammer and trigger is the secret to S&W's DA trigger pull. As the spring compresses and pull weight increases, the force is shifted to a different leverage so the pull remains the same. Most DA revolvers have a problem when the spring stacks and the strut comes into line with the trigger so it is lying on the trigger, increasing the pull. S&W avoids that.)

Jim

 

[madcratebuilder]

Just a follow up to let you know that Numrich supplied a DA sear that still had enough material for me to fit it. Success, this is the first time I have fit this particular part. Not much tolerance between to long, and ah heck, to short. Thanks for the advise gentlemen.
I was hoping that the owner may want to sell this revolver. I don't think he well after feeling the trigger. This came out very nice, a little more DA pull than the short action guns, but not bad.

 

[Old Fuff]

An Old Fuff hint:

Take the mainspring out of your model 10, and put it in the old Military & Police. Screw in the mainspring strain screw and and back it off no more then a half-turn. Then see if the double action hasn't improved.

"Back when..." mainsprings were heavier because primers often needed a harder blow. The above modification won't reduce the M&P's reliability, but don't try it on later short-action guns.

 

[madcratebuilder]

Thanks Fuff, I haven't swapped springs but I did back the strain screw off about 3/4 turn. I want to get out this afternoon and test fire it.
You can definitely tell it has a heavier hammer fall.
The new hammer most be a half a thou wider. I can feel some drag when you give the side plate screws a finial tightening. I'll dry fire it a bit and then look for the high spot. Didn't make any difference what tightening sequence I tried. It's just that last two inch pounds on the last two screws that bring the drag in.
Not a bad looking old girl. The front sight is a copper? bead, marked MARBLE 35-0, other side SHEARD. It is pinned to a soldered base. I assume this is after market.

 

[Old Fuff]

Oh dear, I have awful news... !!

That's an ultra-desireable target version of the Military & Police model. The front sight base isn't soldered on, or at least it shouldn't be, as it was part of the barrel forging. The front sight blade was cut off and the base slotted at the factory to take a pinned blade. The blade itself is an aftermarket one, but it could have been installed at the factory.

The hammer is supported by bosses on each side, one on the hammer stud (pivot pin) and the other on the sideplate. These are the only place the hammer sides should touch, and a little Dykem will tell you what needs to be done, Be sure to keep the hammer centered, or one side or the other may rub, and you don't want the firing pin to rub on the side either.

When that revolver left the factory it had a super-tuned action. Too bad the kid messed it up.

Be careful with the mainspring strain screw. It isn't intended to be used for adjusting mainspring tension. Among other things it's intended to keep the spring correctly bowed, and the amount of bow is very important.

 

[madcratebuilder]

The sight base is integral now that I put my glasses on
I'll take a real mic to it tomorrow and see what I have.
Maybe the owner can be talked into selling it. I sure shoots nice. I need another Smith .38 like I need another open top Colt.......come to think of it, I do need some more open tops.
Thanks for the help my friend.