Took out a brand new SP1 upper today to sight in the scope, it would not feed the first round into the chamber. It strips it off the magazine, inserts round but bolt will not fully close. Since there is no forward assist I couldn't shove it in nor could get it out except for the slam butt method which ejected the round, When I inserted round in chamber then let bolt carrier go it locked perfectly as it did when firing. I was not riding the bolt when chambering, I only had ten rounds in the magazine. Is this normal for a new upper?  thanks

rk

Use 5.56 or 223 ammo.

Did you try a different magazine?

its probably your mags....i had the 10rnd bushy mags and i had the same problem

I only had one magazine with me, thanks. Will try.

rk