This is the 3 round .300 Win Mag magazine for the Browning BLR.
Compatible with all post 1981 BLR models. Browning no longer support Pre 1981 format magazines.
Browning moved to an AR-15 style rotating bolt in 1981 which locks into the barrel and allowed use of an alloy receiver. Earlier models had receiver locking bolts (and steel receivers) which used a different mag fitment.
Made from blued steel this factory replacement magazine is a double stack design wth a stainless follower.