I have an SBR built on Midwest industries upper and lower with a 10.5 inch barrel. I use the weapon as my daily patrol rifle. Upon taking ownership of the gun it ran flawless. I qualified with it and practiced with it all without a hiccup. After approximately 750 rounds I started experiencing failure to feed and failure to eject. I stripped it down and cleaned it very well. This fixed the problem for approximately 60 rounds, then it returned. I have tried different ammo with no effect. I have noticed that it tends to rear its ugly head once the gun is warmed up a bit. It will run fine for the first mag or so then starts the failures. To be more specific about the failure, it will fire and eject but then fail to strip the next cartridge out of the magazine. (Yes I have tried different mags) a few things I have read says my buffer spring is too weak, some say it’s too strong. Some literature points to undergassing. Some points to overgassing.
PLEASE help. The guy who built it was of no help and has since shut his doors. I know the collective knowledge here has to have an answer or a solid suggestion.
Thanks
Bookmarks