Battlemags work for 300 blk from my research, for .338 and .243 research suggests pmags and ar15 / ar10 mags for the specific round work. Dont see why Troy doesnt sell them for .338 or .243, also would help a little if you included the model of firearm your referring to.

Michael, if the manufacturer does not make the magazines for their rifle, they will have a maker/supplier. Just give them a ring to either buy extra or get their maker/supplier contact info.

Sir, Most semi-automatic or bolt action rifles come with one {1} magazine from the factory. You can easily use any 223/556 magazine to load and chamber 300 Blackout rounds. Most .338 and .243 magazines are company specific generally. You may find an AR30 magazine that will load and chamber the huge .338. Most .338 and .243 mags max at 10 rounds. Easy to not shoot a lot of .338 at $4 to $10 a round.

Battlemags work for 300 blk from my research, for .338 and .243 research suggests pmags and ar15 / ar10 mags for the specific round work. Dont see why Troy doesnt sell them for .338 or .243, also would help a little if you included the model of firearm your referring to.