I just finished my xm16e1 clone and made some dummy rounds for it. When I pulled the charging handle back and let it go the round wouldn't chamber all the way. I tried it again with another one and the round got stuck. I had to hit it on the ground to get it out. The casing is a little scratched. The barrel is a brand new green Mountain A1 barrel. I'm not sure if maybe the chrome went on a little thick? I cleaned the barrel when I first got it. I don't see anything unusual in the chamber. Any suggestions?

How did your headspace check go?  If it went ok, check the dummy rounds you are using against specs.

I haven't headspaced it. I'll take it somewhere and do that. I dropped an m855 round in the chamber and the base sticks out about a quarter inch or less.

It's supposed to stick out 1/4" or so. It's is very rare for any new rifle barrel not to work with a new G.I. bolt. I suggest you clean the barrel and chamber thoroughly if you haven't done so already. Most new ammo is quite a bit shorter than SAAMI minimum headspace and it's nearly impossible for the bolt not to close on it. Reloads can fail to chamber if they weren't sized enough.

Does the bolt go home on an empty chamber? If not some crud is stopping it or the barrel extension has a flaw.

Yes it closes on an empty chamber. Bother the barrel and bcg are brand new. The bcg is a rra chrome carrier. I'll try put some live ammo in it. Maybe the rifle will just require small base dies.

They are not crimped. I didn't size the brass myself either, it's from a company that does that already then sells the brass. I'll size some myself and try. Thanks!

Hopefully that is all it is. A loaded round should fall into and out of a clean dry chamber by itself.