Hey all,
For those Sig P938 owners, I did a trigger job on mine and it came out great! Stock pull was 7.5 and gritty. Got a stainless trigger from partsproduction.com, Wolff reduced power hammer spring (20lbs), and took it apart, polished all contact points, and frog lubed. Current trigger pull is 4.5 and nice, smooth and crisp. LGS gunsmith verified and approved
I used the vids on youtube, and a few threads over at sigforum to do it. I've got experience working with glocks, but had none whatsoever with 1911 style guns. It's def more complex, and took a little longer, but after multiple assembly/disassembly to adjust things, I've got it down to a science. A couple things I noticed:
1. The reduced hammer spring, polish, & frog lube only dropped the trigger pull down to 6lbs. I wasn't happy this first go around so I went back in, polished a little more, and did 2 more frog lube treatments.
2. The biggest change in reducing trigger pull came from tweaking the sear/disconnect spring. My advice would be to make small adjustments at a time, re-install, and check. Sure it's a hassle to have to assemble/reassmble each time, but now I am confident I understand how my gun works. I looked at some 1911 sear spring vids and used just a plain pair of pliers to adjust the tension.
3. If you get the parts production stainless trigger, it comes with a small post with a rounded head to place inside the trigger bar spring. I found that even after polishing this part, the trigger was gritty. I took it out, and it's smooth as butter. It looks like the trigger bar comes into contact with more metal surface area with the pin in the spring vs. just the spring itself. It didn't change the trigger pull weight, only the gritty feeling.
4. The trigger pin was a pain. I've read on other forums of people having the same issue. I even broke one punch trying to get it out. I ended up finding a cupped starter punch and worked like a charm. I also dropped some oil in and let it sit for an hour. My advice would be to def use a cupped punch... and know that you may really have to wail on it the first time. Every other time after was easy.
5. If you lose your trigger spring, feel free to PM me. I have extras. Ask me how I got them. I heard it shoot out while punching out the trigger bar pin and spent 2 hours looking for it. I finally gave up and ordered a few from Sig (to justify the S/H), went back to start polishing and miraculously the spring was still in the trigger! But, I'm sure other 938 owners may run into this problem so feel free to PM.
6. Frog Lube is the best. Currently working on Frog Lubing all of my other guns at the moment.
Safety & function checked, then took it out after I finished and shot 300 rds of various ammo (WWB, Wolf, Fed, Fed Hydrashock, Speer +P with no malfunctions.
That's it, next time I do a detailed clean I'll see if I can get a video or some pics, but if you have questions feel free to PM me.