BudsGunShop.com - Multi caliber

Dennis, Yes multi-caliber lower can be used on whatever you build. 300 BLK, 224 VALK, 5.45mmX39mm, etc. Whatever caliber AR you want to build.

A Multi caliber lower can accommodate several different caliber uppers such as 223/5.56 , .458 SOCOM, .50 Beowolf, 7.62x39, 6.5mm Grendel, 300 AAC

Dennis, "Multi Cal" means this lower can accommodate several different caliber uppers such as 223/5.56 , .458 SOCOM, .50 Beowolf, 7.62x39, 6.5mm Grendel, 300 AAC etc.

Dennis, since it is just a lower receiver you should be able to use any cartridge that fits in a normal AR 15 magazine so long as you have the proper upper receiver. In addition to 5.56/.223 that could be .300 Blackout, 6.5 Grendel, 6.8 SPC, .458 SOCOM, .50 Beowulf, etc.