New to this forum and just got some great info on modifying the trigger on the MP 45 I just bought (thanks Dan!!!). Anyways I realized that I had a Sigma in the safe that I never shot because the trigger was so bad that I could not stand it. I have built several 45's ARs and 10/22s but the MP was the first plastic gun I messed around with besides the simple glock stuff. The MP gave me some confidence so I started tinkering around with the sigma and was able to make some significant improvements very easily. I have not seen any action in this section for awhile so if anyone is interested let me know and I will post pics and instructions. I would love to hear what everyone thinks.
Sigma Trigger Fix Found!
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I have a neighbor that purchased 2 sigmas rather than M&P's against my advice. He was asking me yesterday what he could do to make them more like the "Expensive Version". 
I am certain he would appreciate any advice you might have to offer. :?
My plan was to hit them with a fine stone etc. then with a big rock. 8)
Anyway please do post more info.
:twisted:
I am certain he would appreciate any advice you might have to offer. :?
My plan was to hit them with a fine stone etc. then with a big rock. 8)
Anyway please do post more info.
:twisted:
i did a trigger job on my sigma, my first gun. Everybody said, if you can learn to shoot a sigma good, you can shoot anything. I used wolf springs and installed night sites. I think the sigma's are not bad weapons. Just need some tinkering. Oh and the hogue grip felt good but i had better luck with agrip.cgfop said:
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cgfop said:
I would like to see the pics and instructions please...
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Srigs said:
I do too...and it is my primary carry gun...I just want to see his instruction for lighting the trigger...just curious, no other reason. I have over 2500 rds through mine, and except for the recent "cheap ammo" with steel cases, I have had zero failures with anything brass.
Went to the range yeasterday because I wanted to do a test fire before posting instructions and put 150 rounds through it with no problems. What I did was very simple. The only problem I can think of encountering is the trigger not resetting in an extremely dirty gun. I started out with polishing the sear. After the slide is off and before disassembling the sear, pull the trigger and watch the action of the sear. The long flat spot on the rear of the sear that runs at a 45 is the part that needs to be polished. It is in contact with the poly and allow the sear to move rearward to cock the striker and downward to eventually release it. Polishing this area gives a much smother trigger pull and gets rid of the grittiness. First I hand sanded this area with 220 grit paper then 320, 440, and finally 600. Then I polished it on a full size buffing wheel holding the sear with vise grips. Careful not to catch an edge or it will go flying. Try going at it from multiply angles to get as much as the surface as you can while not hitting the face of the sear. I would try and keep the surface flat and not to round out the edges as that will lead to point loading on the poly and premature wear. I did not feel it necessary to polish anything else as in the above referenced post. Then I took a few thousandths off the top of the sear. This was done for two reasons. First to give it a nice, clean, sharp edge for a crisp break. Second, by removing a small amount of metal from the top of the sear you are able to control where the trigger breaks. Be aware that this gun is like a true double action gun in that the striker is being pulled by the trigger before it is released. Because of this you will be reducing the amount of energy that the firing pin will have as the trigger breaks. So don’t go over board or it will break so early that you will have light strikes. Unless you feel confident in machining off a few thousandths of metal at a time you should skip this step as it will not reduce the actual trigger pull weight. The next two things are what really lighten the trigger pull. The sear is pushed upwards by a double spring. Upon reassembly remove the larger outer spring and assemble without it (picture 3). Second, the sear and spring assembly is pushed forward by the spring in picture 4. Upon reassemble also assemble without this piece. This means that you will be reassembling your gun without two springs that Smith and Wesson originally felt the gun needed to operate to their specs. Please keep that in mind when doing this. Also keep in mind that their original specs call for a 10lb trigger and doing this will result in a substantially lighter trigger. I have only put 150 rounds on this trigger set up and I keep all of my firearms exceedingly clean. Will it stand up to 2500 rounds in a dirty gun? I’ll let you know when I get there. Like I said the only problem I can foresee is a failure to reset. And since there are no permanent altercations made to the weapon it can be put back to stock condition at any time. But as always use your best judgment.
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