AR build question on tight front pivot pin.

[teddy12b]

Last night my brother in law came over to the house with his rifle kit that he'd bought locally that day. He's been wanting an AR for well over a year now and for him to get this package together was an accomplishment a long time in the making.

So anyway, we assemble the lower and he gets to see how everything works which was really good for him and really helped him understand how the rifle works. We went through everything, but the one thing I noticed and I didn't say anything to him because I didn't want to call his new baby ugly, was that the upper to lower fit would be loose & tighten & then loosen when rotating the two halves on the front pivet pin. Was it a big deal, no. Was it anything I've ever felt on any other AR-15, M4, or M16 I'd ever felt in my life, no. It wasn't bad, but I could feel that something just needed to be smoothed out.

I've never came across this issue and I wasn't sure if it was the upper (CMMG) the lower (PSA) or the actual fron pivet pin itself. In any case I put a dab of oil there and worked it a couple more times, but it didn't seem to do a whole lot.

Any suggestions?

 

[chuddly]

bent or dented front pin??? it would almost have to be that because even if the holes weren't aligned it wouldn't get tighter and looser by rotating the pin.

 

[Don]

I had a delaware lower I had to run a 1/4" drill bit down the holes because it was phosphated too small. The drill made everything all nice again.

 

[mjelder]

I would say it is less likely a loose pin and more likely an inconsistency in the holes. Maybe the mold had a slight 1/64th of an inch error in it or had a bubble in whatever the lower is made out of that caused the pin hole to go out of round but is not visible to the eye. Id hit it with a drill bit if you are feeling angry or if you are feeling loving maybe try to polish it out or use a really really fine grit sandpaper