When reloading with the M4 instead of swapping magazines the current magazine attached to the gun will just take bullets from other magazines in the inventory. Also conversely trying to reload with the .45 pistol will not swap magazines and must be done manually and the Mosin clip must be ejected to reload any amount of bullets into it, ex. 2 bullets can not be added to a current 3 round clip in the magazine without first ejecting the 3 bullets then loading 5 in. (Not sure if the Mosin magazine is intended to do this though)