The Sig 522 trigger breaks clean but my problem with this rifles trigger is the HEAVY  first stage take up in the trigger that makes it hard to tell when  the second stage or break is coming.

Since the safety blocks the trigger movement and the hammer/sear break is clean, all it needs is a spring change for a really nice trigger.

I didn't want to modify the heavy stock spring, and Sig isn't the greatest place to get extra parts or deal with warranty after mods,,, so I saved the stock spring and  modified a used AR-15 hammer spring from the parts bin .

(Top is Sig and bottom AR)



Then I cut and bent the lighter AR spring to fit the hammer then curved the front to ride the shaft of the safety. I left the front "out" the way it was and coiled it "in" when installing the safety  back in.



(A word about springs, they are brittle and can break so sometimes its best to heat the part you are bending.)



Here is a pic of both stock spring (top) and lighter AR spring (bottom installed)



When removing the safety you have to work on the left side and remove the roll pin, remove left safety lever pull the safety shaft out from left to tight.

To remove the trigger you have to push down on the safety detent spring then remove the pin.

When installing the trigger pin, make sure the safety detent spring is hooked over the top of the hammer then under the groove in the trigger pin then up on top of the safety shaft dimples.

**MAKE SURE you test for trigger and disconnector for reset** and as always, test any modded firearm loading only two rounds at a time to test for safety at the range.

The trigger is now MUCH BETTER and  more like a two stage AR trigger  where the pull in take up is lighter and you can feel where the 2nd stage or the break is and you can feel the reset for follow up shots.

Great Post!!!      So how does it work after the mod??? I will give it a try if it works better than the SIG spring!!

Awesome! I agree with your assesment of the 552 trigger pull.

I know what I am doing this weekend. Thanks for the tip.

Haven't had a chance to get to the range yet but the safety checks are good and the trigger much more predictable now.

Any range report yet? Curious how the trigger mod is working.

I've had too many other things on my plate to try the mod yet. Between shooting matches and building some target stands, I have been busy the last couple of weekends. I need to get going on this though.

Oooops sorry, Yes I took it to the range and tested it through about  200 rounds  and it works perfect, in fact I think I'm going to lighten the spring even more . You do feel some creep from the hammer sear engagement but it's very easy to just pull through quickly now. If I knew I could buy an extra hammer sear, I would stone it an break the edge to make it perfection but it's pretty good as is.

Rocker, you ROCK.! It appears that you have also solved the Sig556 heavy trigger spring issue as well as the 522 trigger issue.. Superb 'thinking out of the box'!!!!   Now, I am fucking jealous that I didn't think of this, but I did not. You have kicked ass, and  this is just awesome on your part!

This is an awesome mod.  I used a mil-spec spring from an AR parts kit, my first attempt still feels a little too strong - but its alot better.

While I was doing it I managed to perforate my thumb with a sharp spring, I knew it was likely and it just slipped anyway.  I was thinking, hey this would be the perfect mousetrap, and snap!  So be careful with this mod, springs are evil things.  

Well, I finally did it. I made and installed my trigger spring. It was a little bit of a pain getting the long end of the sping bent up and around the trigger picot pin and hold it under the safety lever pin while putting the safety back in.

Here is my spring under the factory spring.


The trigger pull is noticeably lighter now. A little creep but much better than the heavy pull from before.

Looks real good, nice pic too.

I'm going to find some  spring stock sometime a go a little lighter. I'd like to stone the creep out but until trigger groups are available I don't like to one shot risk. The mod sure is better with double taps and just pulling through.

Thank you!  This info is 95% of why I joined the AR15 forum and here it is on the first night of looking.  
I was about to give up on my SCM (yeah - I live in one of "those" states) due to the trigger.
Now I have a good weekend project.

Ailean

No prob , mine is still working great but I still need to find some spring stock . I'll bet there will aftermarket triggers soon .

What about these "Reduced Power" AR springs? Brownells.com
There like $10 to the door.

Thanks for the idea,this is a great mod.