This is cross posted but I got no responses so here I am.
I am new to AR building and am having (possibly) a problem and want to tap the collective wisdom.
I have 3 Anderson Manufacturing stripped receivers. Had them in a drawer for a couple of years. Recently bought a kit from PSA and built the lower. All went well. Gun functions. Took it to the range and not a single hiccup. Except, Magpul PMags (Gen3 only--Gen 2's work ok) will not drop free. They are tight going in and coming out. I have mags from a bunch of other manufacturers, metal and plastic, and they all work fine. Also, I have several other AR's (S&W M&P 15's) and the PMags drop free on them with no problem.
I called Anderson and they want me to fill out paperwork and then ultimately send them back, but I wanted to have a better understanding of what was going on, so here I am.
I have pondered on it a while and have figured out what I believe is the issue. The groove, inside the magwell (stolen pic)
on the Anderson receivers is 24.35mm from inside the groove to the opposite inside wall and on the S&W Ar's is 24.66. That very little bit appears to be making the difference.
So, could some of you who have some calipers take a look and see what measurements you get. I really do not want to mess with sending these back, especially if they are just going to tell me they are within specs and the problem is Gen 3 pmags.
Thanks to one and all!
I am new to AR building and am having (possibly) a problem and want to tap the collective wisdom.
I have 3 Anderson Manufacturing stripped receivers. Had them in a drawer for a couple of years. Recently bought a kit from PSA and built the lower. All went well. Gun functions. Took it to the range and not a single hiccup. Except, Magpul PMags (Gen3 only--Gen 2's work ok) will not drop free. They are tight going in and coming out. I have mags from a bunch of other manufacturers, metal and plastic, and they all work fine. Also, I have several other AR's (S&W M&P 15's) and the PMags drop free on them with no problem.
I called Anderson and they want me to fill out paperwork and then ultimately send them back, but I wanted to have a better understanding of what was going on, so here I am.
I have pondered on it a while and have figured out what I believe is the issue. The groove, inside the magwell (stolen pic)
on the Anderson receivers is 24.35mm from inside the groove to the opposite inside wall and on the S&W Ar's is 24.66. That very little bit appears to be making the difference.
So, could some of you who have some calipers take a look and see what measurements you get. I really do not want to mess with sending these back, especially if they are just going to tell me they are within specs and the problem is Gen 3 pmags.
Thanks to one and all!
