loose fit between upper and lower

[12ptdroptine]

I have noticet that the fit on my LR308 isnt tight at the rear of the upperwhere it pins to the lower. You can actually move it up and down to the point where you can hear a little clunk..and some side motion. Never knew to look for this. Front pin is tight but the back one sure isnt. it hasnt had 100 rounds through it. is this common?

Thanks Drop

[Robocop1051]

Yup. Common enough that someone invented this...

Accu Wedge

[Jgun]

On my small frame AR builds, I routinely fit oversize national match pins available from Armalite. Another option is the expanding takedown pins available from Demon tactical, and others. Unfortunately, I have yet to see them offered for the large frame AR's. If any members are aware of someone selling OS pins for the .308 AR, Please let me know.

[JMoto]

Another option is to bed the receiver either the upper or lower. I have done it on a couple but there are other options. The main thing I like about the bedding is that it is still a tooless takedown should I need to strip it in a hurry.

[1010]

mine had a little play, i just installed a .006 shim between the upper and lower at the area behind the rear pin..now it locks up tight.