i picked up a RAR when they first hit the market up here and that was the first thing i noticed, the aftermarket mags where either tight or didnt fit.
after looking at the gun for a bit i realized that the reason was the sides of the magwell.
on the 10/22 the mag well opening is open to the wood on the sides so the mags can vary vastly on their width and have no issues.
the RAR on the other hand is a one piece mag well and as such has a very tight tolerance for mags.
like you said the BX-01 is no problem ive run ram-line, steel lips and TI metal mags in mine, all of which where tight but now work.
what i had to do was just use them, run them in and out a bunch and they basically carved away the plastic that was making them tight.
if a fella wanted to get around this fast you could just take a flat file or some sand paper and take 1/32" off of the sides of the magwell (inside).
think i even have a old pic up about this from a year or so ago, ill go look.