Only Colt magazines fits my lower.. WHY ??  when removed the upper from the lower any magazines will fit. Im not a big fan of Olympic Arms myself but this is the only one semi auto M16A1 style lower I have found for xm177e2 clone project.  My A1 upper is 100% Colt upper BTW. just replaced the magazine catch but  no help..  whats wrong with this lower ? any idea ??

I have heard a lot of bad about Olympic on this forum, and only on this forum. I have a home built Oly, receiver made in '90, it has no problems and never has.

You never mentioned what other types of magazines you are using besides the Colts. Are they USGI? Are they cheap mags? Olys have had tight mag wells on older rifles, but not always or all the time.

Olympic also has a lifetime warranty on there lowers, call them up. In this day and age, I always use lowers besides Olympic, but the one I have works just fine.

I also read once that the reason Paul McCartney didn't wear shoes on the Abbey Road album cover is because he was dead

Quoted: I have heard a lot of bad about Olympic on this forum, and only on this forum. I have a home built Oly, receiver made in '90, it has no problems and never has. You never mentioned what other types of magazines you are using besides the Colts. Are they USGI? Are they cheap mags? Olys have had tight mag wells on older rifles, but not always or all the time. Olympic also has a lifetime warranty on there lowers, call them up. In this day and age, I always use lowers besides Olympic, but the one I have works just fine. I also read once that the reason Paul McCartney didn't wear shoes on the Abbey Road album cover is because he was dead

All USGI 20 round mags. only COLT mag fits my lower. I have 2 Olympic SGW lowers with SAME problems..

OLy will build you a brand new lower with that serial number for about $100. Their new lowers are very good quality.