Bolt_308 Posted September 18, 2021 Share Posted September 18, 2021 (edited) Hello- new to the group as I just bought my first M4 and brought it home last night! Gun is brand new. Got it home, followed the directions to clean, lube, and assemble. Followed some of the direction here and applied a lot of lube. Right away in working the bolt, something was not right- it was hard to pull back and kept sticking back. Thinking I had done something wrong, I disassembled, watched a bunch more YouTube videos on disassembly/assembly, and then very carefully reassembled. Same issue. Bolt would be difficult to pull all the way back to the locked open position, would ‘hang’, locked back, and it would take a very firm wack with my palm to get it to go forward back into battery. I did a lot of troubleshooting, reading of forums. Made sure barrel fully seated, nut firmly cranked down. I even tried reassembling without the trigger group installed. In running the bolt without the barrel installed, everything was smooth, but when I reinstalled the barrel, and the barrel extension, it would hang/freeze/stick again. Eventually, I figured out that the front of the bolt, is rubbing against the ejector, and there is a gouge forming on the underside of the ejector. I have attached some close up pictures to hopefully better illustrate, as I am still learning the parts and may not have the right name for the parts. If you look closely on the bottom of the ejector, there is a groove forming where it hits and grinds. In searching the internet, I did find a forum thread on AR15.com where it sounds like someone had a similar problem and their gunsmith removed some material on the one part of the bolt where it was rubbing to get it working. Before I do something that drastic, thought I would check here first to see if there is anything I am missing or if this is a common/known problem. I can link to that thread, but wasnt sure the etiquette here for that. Help! I was so excited getting home with a new M4 and have spend the night and this am trying to get it figured out! Thanks! Edited September 18, 2021 by Bolt_308 1 Quote Link to comment Share on other sites More sharing options...
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