Hello everyone.  I have a 30 rd orlite mag that my olympic plinking ammo (55 gr fmjbt) seems to fit in, but the olympic rds are too long to fit my british military 30 rd mag.  Comparing the rds to winchester white box fmj and S&B fmj the olympic bullets are not seated as deeply in the shell and look to be about 1 or 2 mm longer, causing them to drag on the front of the british mag and jam it up.  Any suggestions?  Are the british mags any good, they seem to feed my winchester white box perfectly.  Thanks for all replies.

probably your ammo.

Do a search and look at all the problems people have been having with olympic lately

Some of the english mags will not allow max length loaded ammo in them. They are a little short on the inside length. It varies from mag to mag. The shortest ammo I found is the new winchester value pack 223.

I bought ten of the 30 rd. SA-80 "Made in England" mags from R-Guns, and one would not load: too short somewhere around the fifth cartridge.  

I was using the cheap Winchester white box 55 Gr. stuff.  

The other mags worked fine, just the one bad one.  I sent it back and they gave me a replacement that works fine.

I would suggest replacing the cheesy English black plastic followers with the new "Made In USA" green ones.  There is a world of difference in the quality of those followers.