Convert your AR15 to 22LR in 30 seconds or less. Full drop-in AR15 22LR conversion kit, complete with magazine and bolt/ bolt carrier for semi-automatic AR15 rifles. All CMMG .22 LR magazines have a bolt hold open follower. When using the bolt hold open follower, magazine will only hold 25 rounds. ***PLEASE NOTE*** We will not ship this item to: CO, CT, NY, MA, CA, MD, HI and NJ.