I received my 2 triggers Saturday late. About 7 PM.
The triggers were ordered for my M11A1 and a P229 SAS.
The instructions called for the pre-travel delrin to be filed down to 0.03"
to 0.02" to get a DA reset. The original dimentions of the delrin was 0.065".
I removed the right grip plate, released the pressure off the sear spring
and removed the safety lever since the M11A1 has an SRT trigger system and this way
it would be esier to remove the trigger bar.
I proceded to remove the trigger bar spring, trigger bar, original trigger,
trigger pivot pin, slide catch lever, take down lever, and locking block.
Installed new trigger and proceeded to reassemble frame and then I realized that
the lenght of the pre-travel delrin would not let me seat the locking block all the way.
The gun was decocked and the trigger pivot pin had the notches facing down as always.
Removed everything again and filed down delrin to 0.035". I took a gamble.
Reinstalled everything again and the locking block snapped in with no problem like
I have done dozens of times on all my Sigs.
At this point, the trigger did not reset in DA.
I turned the frame upside down, pulled the trigger all the way back and carefully filed down the delrin with a fine flat and narrow file making sure I did not scratch the frame.
After several tries, SUCCESS !!!, the trigger reset with no pre-travel.
Final length of delrin 0.018".
Next was adjusting the over travel set screw. That part was fast and easy.
Turned set screw with provided allen wrench until the trigger did not release
the hammer on DA. Backed out set screw until hammer released.
Assembled slide and frame together and function tested the gun.
Last thing was to make sure the pretravel screw did not move on me.
I advanced the screw two 1/2 turns towards the back of the trigger.
Dabbed some clear nail polish on the threads, and backed out the screw towards the front 2 1/2 turns.
Total time 1 1/2 hours considering it was my first, very minimal instructions
and careful not to screw up.
Sunday morning I tackled my P229 SAS in 25 minutes !!!!!!
Final delrin lenght 0.015".
CONCLUSION: I am very satisfied with the end results. No pre-travel and my SRT action has been improved by the over-travel adjustment. I am a self taught amateur armorer learning by doing.
I never outgrew my Erector set.
As usual all these parts have the disclaimer that they should be installed by a qualified armorer or gunsmith.