I agree, I may take it back to the vendor this Friday to have them look at it. I'm pretty sure I have it assembled properly, I've triple checked the assembly. When I put the end cap on it does make the racheting sound as it tightens and is very secure, however soon as I start racking the bolt the whole thing slowly comes apart. I was worried about the handguards as well but double/triple checked to make sure they were on right. I'm fairly certain its that small extension piece not holding at the seam. My new tube will be here Thursday so most likely will have it fixed by the weekend. Pretty frustrating to have this problem. Thanks for your responses, if you think of anything else I'm totally open to ideas and input.
Well have a question for the masses. I just bought my m4 and was pretty excited. I read the manual and watched videos to make sure that I assembled the shotgun right and then went out to shoot it. First five shots out of the shotgun and the end cap came loose and barrel started to come off. I checked everything made sure it was tight and have now discovered that the magazine tube extension piece that comes factory is moving allowing the whole assembly to loosen. I have tightened everything and have found that even with racking the bolt it jars the tube loose at the seam where the small piece threads onto it. It doesn't look like its "unscrewing" it appears to be jumping over the threads with the shock of the bolt slamming forward. Has anybody else had this happen? I have ordered a full length magazine tube in hopes that it will solve this issue.