Was function testing my most recent  M4 clone...finally, and had about 4 light primer strikes out of about 25-30 rounds. Was using a mix of commercial, surplus Federal M193, and the BECK Ammo version of the Mk262 77 grain rounds. Beck were no problem, but the commercial and surplus gave me the light strikes. Reloaded them into the mag afterwards and they all fired.

I'm using the ALG ACT with JP yellow springs. Have read that this may occur sometimes with this spring/trigger combo. Anyone else have this issue. I really like the break on the trigger. Particularly after installing the JoeBobs adjustable grip screw. Would hate to have to change the feel of it. Any suggestions?
Full Power hammer spring?
Bob the hammer?
The rifle will be used as a go to gun for defense if ever needed, so I want the reliability, and the same time I'd like to strike a balance and keep the best trigger pull for accuracy.

Full power spring, also make sure you didn't install the hammer spring backward. It's easy to do if your not paying attention, it will give you a nice trigger pull, with intermitent light strikes.

Will check that when I get home today. Thanks.

I will be switching out the spring and retesting the rifle coming up. I was the first range day for the build, so I expected some kinks in it. It will serve as my primary goto rifle, so I most definitely want the reliability from it.

Thanks for all the info gents.