Have seen a few  AR mags for sale that say "don't fit Rock River or Bushmaster".Some of Cheaper-than-Dirts mags come to mind.I want to know why? Have a BM and have run a fair number of various mags thru it w/o any problems.Any ideas? Thanks,Dave

Bushmaster magwells are on the small side.  If you stick with USGI mags you never notice.

Quoted: Bushmaster magwells are on the small side.  If you stick with USGI mags you never notice.

I always thought they were kind of on the larger side.  My Bushmaster magwell is noticebly larger than my Stag magwell.  Anyway, just stick with USGI  mags.  The reason the POS cheap mags don't fit is they are made out of spec.

I always wondered why some mag companies says theirs won't fit bushys

Their mags are afraid of snakes.

I had sanchez, OK, and Colt 30 round mags that would not drop free from My bushmaster but would dropr free from my Fulton, Colt and RRA lowers. I never found a USGI 20 that would not drop free from any Lower.

Those grey parked steel britsh mags ammoman was selling worked fine in all lowers, go figure.

Quoted: Have seen a few  AR mags for sale that say "don't fit Rock River or Bushmaster".Some of Cheaper-than-Dirts mags come to mind. I want to know why? Have a BM and have run a fair number of various mags thru it w/o any problems.Any ideas? Thanks,Dave

This "don't fit" issue is years old now and came about because of the "rib" around Orlite magazines.

Seems this "rib" prevented consistent mag lock-up in some RRA and Bushmaster lowers.

The fix was simply to take your Dremel tool and buzz the little rib down, mags would then work just fine.

Suspect this is what your asking about.

Mike

ps - best advice I can give is save your Orlites and Thermold mags for range use.

Yes I own them, yes I've buzz'd them to get them to fit, yes they work fine (up to a point) and NO they should never be preferred over USGI mags......

Early Bmaster lowers had tight mag wells. I've seen one L11xxxx series but another L13xxxx and later no problems. The tight wells are just well tight. Only an occasional (out of tolerance) mag is snug. Most are fine. I believe orolites are slightly large.

M4-AK

As always,thanks to all.EXACTLY what I was looking for.Now,tell me tomorrow's winning Lotto numbers.