The Sigma Saga Continues...
Wow, this has got to be one of the worlds longest single issue thread postings.
I have had my Sigma SW40F since 1995 and really like it. It has spent most of its time in the Blue Carrying Case and I seldom fill the 16 round mags due to weight issues. If you "can’t hit with eight, it may be to late". Since finally going for and getting my CCW last month here in AZ, I have started going to an indoor range on a weekly basis and have really gotten to know my Sigma. Its trigger pull finally got me looking for answers, so here I am with my two cents worth.
Even though I have cleaned it many times I never really examined the working, closely. Shame on me. I must say now I see why S & W may be so quick to fix trigger issues with no questions asked. Poor “Quality Control” has been what my Sigma has suffered from all these years and I didn’t use it enough to know it.
Here is what I found. First, the “Striker Safety Plunger” and “Safety Plunger Spring” were binding and rough in their action. When I removed them from the slide I found lots of small metal chips. The machined recess for the safety plunger was apparently never cleaned well prior to the slide assembly.
Second, the raised tab on the “Trigger Bar Assembly” was barely contacting the striker safety plunger, hence the plunger wanted to “bind” a bit before it finally got depressed during trigger pull. I re-aligned and polished the tab on the trigger bar that contacted the safety plunger for a smoother more positive action. Be careful here, because if you go to far you will create a bullet feed problem.
Thirdly, I polished the appropriate sear block and striker assembly surfaces and the feed ramp on the barrel. And lastly, I purchased a Wolf Standard Recoil Spring (17 Lb.), Steel Guide Rod and 4.75 Lb. Striker Spring to replace the stock striker spring from S & W and the plastic recoil spring assembly.
Well, it was worth all the effort. My SW40F is now a really great carry piece. Trigger pull is smooth, but still firm, which is what I like. For those of you with weak fingers who use the Sigma as your primary carry, and want a light trigger, get a different gun. Non-Standard Striker springs are for competition use only and should not be used in the Sigma for any other purpose. Don’t have to learn the hard way.