If a gun manufacturer in Canada were to make a .458 socom ar pistol that was commonly available, then they could also have .458 10-round pistol magazines made specifically for it. Sure would sell a boat load of those magazines.![]()
Wouldn't make a damn bit of difference. In order for the mag to properly feet the .450 Bushmaster, the spring follower is different than that of a .223. Though I'm not completely 100% certain, if you modify that mag beyond the factory specification (to make it now work with .223 ammo), I believe you've just created a prohibited device.


















































