I am buying a Chinese Norinco NHM-91 and we could not move the little post holding the muzzle nut in place. Or whatever it's called (noob here). I found on a site that some are welded in. I didn't get a good look at it before I left the shop so I don't know. I also found some info on another site that said to get it out by taking out the sight. Any advice? The dealer I'm buying it from wasn't familiar with it. I would really like a brake on there.