AR question?

[CP]

How much "wiggle" if any, should there be between the upper and the lower?  Every AR that I've handled seems to be a bit loose in this interface.  Anything to worry about?

[mountainman]

Accuwedge is the standard fix for this issue.  I designed a lower a few years back (BlackMtn) which incorporated a simple reccessed allen screw to tension out this space. Worked very well

[Yondering]

A little wiggle is normal, but a lot of people, myself included, find it annoying.

Put a small O-ring around the front lug of the upper; it acts as a spring to keep the joint tight. They are cheap, keep a couple extras for spares because they wear out sooner or later.

[pianoman9701]

Take out the little slack there is and it's likely going to be more difficult to break down without tools. This may not be a problem for you. I like having the ability of being able to take it down quickly in the field without effort. 

[Yondering]

Take out the little slack there is and it's likely going to be more difficult to break down without tools. This may not be a problem for you. I like having the ability of being able to take it down quickly in the field without effort. 

True with the conventional methods of various shims, allen screws, etc, but not true of the O-ring trick. I agree about wanting to be able to take it down without tools; the O-ring allows you to do that. I also like to install extended takedown pins on my rifles to make this even easier.

[pianoman9701]

Good to know. Thanks.