Originally Posted by
Joe_Friday
A local law enforcement agency is having a problem with their M4ergies that I am seeking advice on.
Stats: Original Colt M16A1, fixed stock, 20” bbl.
Mods: DPMS 11.5” upper w/ full auto bolt and carrier, aftermarket buffer tube, H buffer and spring.
Mags: USGI 30 rd. aluminum
Ammo: 55 gr. FMJ, factory new, various manufacturers
Problem: With DPMS 11.5” upper installed on Colt lower and in FULLY automatic mode, weapon will fire the first round. However, all subsequent rounds suffer from light primer strikes and do not detonate.
It should be noted that Weapon will function flawlessly on semi-automatic only with DPMS installed on Colt lower. Also, Weapon will function flawlessly with original Colt 20” upper in both semi and fully automatic fire.
Any ideas?
Oh yeah this has happened with three seperate weapons also.