.338 SOCOM/.375 SOCOM/.458 SOCOM/450Bushmaster/12.7×42 Center-feed follower for Lancer 5.56 magazines. CNC machined from 6061-T6 solid aluminum bar stock. This follower used in a 20rd 5.56 Lancer magazine, will hold 7 rounds of big bore ammunition. In a 30rd 5.56 Lancer magazine, it will hold 11 rounds (11+0) of big bore ammunition.
We only recommend using the short (10rd 5.56) 4 round magazine for the 450BM. Longer magazines can cause feeding problems with the 450 Bushmaster and the followers will bind up in the 20/30rd Clear and Translucent magazines when using 450BM ammo. The SOCOM is a much better designed cartridge for use in the AR-15 magazine and subsequently, has no issues with any capacity or type of Lancer 5.56 magazine.
Note: If the Tromix center feed follower is installed in a Lancer 10rd 5.56 magazine, it will hold 3 rounds of 458 SOCOM ammunition (3+1), or 4+0 rounds of 450 Bushmaster ammo.
However, the Lancer floor plate retainer contains a 1/2″ long travel limiter stop, and if removed, will bring the capacity to (4+0) in 458 SOCOM and 4+1 in 450 Bushmaster, with the Tromix follower installed.
Keep in mind, if this modification is made, when the standard 5.56 follower is reinstalled, your magazine will now hold 12 rounds of 5.56 ammo.