Bought a keyhole upper new, added a new Colt 20" govt profile barrel. Also added YHM freefloat tube. Also bought a Colt bolt carrier and colt bolt slightly used. Put new rings on it. Took it to the range today and was alittle displeased. Pull charging handle back let go and chamber a round. Pull trigger and round goes off. Bolt does not move. I tried a carrier and bolt from my Hbar and the carrier moved back about an inch then stops. I have checked everything i thought might be the problem. Plugged up what i can and used air. Everything seems good. One thing i noticed was the carrier i bought is a shrouded type. That's the one that did not move at all. My Hbar is unshrouded. I was using white box wwc ammo.