Springs install as such (make sure that the coil orientation of the springs are correct), and make sure that you have the disconnector spring installed large coil side down into the back trigger tail slot, under the disco tail.









Also, when you have the FCG back out to check the install, dry fit the pins to the parts, and make sure that you do not have burs on the parts, hence pins not moving freely in the parts.  When you go to install the FCG parts. lube them on the heavy side with CLP, including the pins and the channels of the parts.



Once you do have the parts back in and only the lower receiver in hand,
cock the hammer back, set the selector to save, and pull the trigger will all your might.  The hammer should not release!!!!

Now flick the selector to fire with your finger off the trigger, cock the hammer as far back as it will go and hold it there, point the front of the receiver straight up, pull the trigger back, and slowly bring the hammer back up.   If you have the disco spring installed correctly, the disco should now be holding the hammer.

Keep holding the trigger back, leave your thumb in front of the hammer, and now slowly release the trigger.   The disco sear should release the hammer back sear, and the hammer should be caught by the front trigger sear and the bottom hammer lob sear.  Do this test a few times, and make sure to keep your thumb in front of the hammer in cause the hammer sear misses the front trigger sear so the hammer does not go crashing into the front of the receiver cavity.


If during the slow trigger release the hammer does miss the trigger front sear and crashes into your thumb (that is protecting the front void wall of the lower receiver), then you have a disco out of time, with the disco sear releasing the hammer too soon, and the front trigger sear not in the correct position to catch the hammer when it it released from the disco.  We can cross this bridge if needed, but the quick check to make sure that the disco is timed correctly, when you cock the hammer back past the disco sear with the trigger not touch, the disco and back hammer sear should just miss each other by the amount of a human hair.


Free gap between the disco and back hammer sear too large on a free gap test, and again, you want the two to miss only by that of a hair, or even to lightly kiss as the hammer passes the disco sear if fine.

When checking to see if the disconnector spring is in the back top of the trigger, make sure it is the correct spring and that it is installed the correct way.

This is a pic of a bolt catch spring.  It is basically a cylinder in shape.  It is generally softer in tension than a disconnector spring, and doesn't have enough pressure to reliably run a disconnector if it's mistakenly installed into a trigger where the disconnector spring goes.  



This is a pic of a disconnector spring.The disconnector spring is a captured spring. It is flared out wider on one end, this makes it capture and retain inside the trigger.  The disconnector spring is installed into a trigger with the wide flared out end going into the trigger first (facing down if you are looking down into the lower receiver at the top of the trigger) so it captures or retains in place, and the narrow end of the disconnector spring faces up so the narrow end of the spring can compress and expand freely to reliably run the disconnector.  The disconnector spring is also generally stiffer in tension when compared to the bolt catch spring.  


CY6
Greg Sullivan "Sully"
SLR15 Rifles
TheDefensiveEdge.com
(763) 712-0123

You mean like the one we already have???
http://www.ar15.com/forums/t_3_66/241858_New_Trigger_and_hammer_pins_walking_out__Why_my_rifle_is_not_igniting_the_primer_.html