If you could provide some details on the rifle, it may help us figure out what you have going on.  Is this a factory built M16 rifle, or something that started as a semi-auto that a FFL/SOT manufacturer made into a full-auto, or do you have a drop in auto or some type and if so then what type?  Then do you have all the correct parts, there are 7 parts to make a full-auto (Drop in auto sear configurations like a lightning link may differ), but these are a receiver, auto sear, auto hammer, auto trigger, auto disconnector, auto safety selector, auto bolt carrier?  Lastly is this an full auto trigger group, 3 position burst trigger group, or one of the 4 position burst and full auto trigger groups?

Is the auto sear installed correctly with the spring in front of the safety selector?



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

Also need to add, roughly how many rounds through the rifle, and if a lot then have you done a full cleaning (including removing the trigger group to clean underneath and confirm there isn't something like a blown primer floating around), and when was the last time the buffer spring (action spring) was replaced?


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

Lets start off by Who did the conversion on the lower in the first place, and is this a form 4 weapon to you, are is this still sitting on a Form 3 as a Post sample with you as FFl SOT.

On Anderson upper, need a photo of the bottom side of receiver,to make sure it does have the sear cut in the first place.


Next, what FCG in play, is this an A-1, burst, or 4 position FCG group, and photo of it installed is needed as well.

As for hammer firing pin contact pads, should be riding the bottom of the carrier at all time as the B/C is  coming back and moving forward.  
If in semi , then hammer is lowered by bottom of carrier for disco to catch it until trigger reset, and if set to full or burst, then disco is cam'd out of position, and the auto sear is cam'd into play for the hammer tail hook to be caught by the auto sear instead.  Hence hammer is always lowered lower then these two catch positions, and that done by bottom of B/C as it comes back/moving forward, until the bolt is just about to lock up.

As for the mix match of parts, will not be plug and play, and once we figure out why the auto sear is not working correctly to retain the hammer back until the bolt just about locks up with selector on full and trigger head back, then can bring the auto sear release in to spec next.

To add, need to make sure correct buffer and recoils are play for receiver extension in play, and on full charging handle pull all the way back, face of the bolt should stop 1/4"~1/8" in front of the back edge of the ejection port window, and last inch of CH pull should be the same tension as the middle of pull.