I just read the thread on head spacing. I just put a barrel on a new reciever, shot it and had no problems. I also just built a new upper, havn't shot it, but now I'm worried that something will be wrong. It's a Bushmaster. I don't have the guages or the knowledge to check head space. The armorer said he would check them tomorrow. He told me that the parts are supposed to be drop in but it"s always good to check.

I know Bushmaster is a little higher price but it's what I've always had and I've never had any problems with them. My new build is a 14.5" M4 profile. Seems a lot lighter than my heavy barrel 16". So many options out there I don't know where to stop!