Butler Creek has three ways to load MSR magazines and none involve your thumbs. The Butler Creek ASAP Universal AR15/M16 Magazine Loader fills up mags almost as fast as they can be emptied. Loose ammo can be loaded one round at a time with a simple click or engage the loading arm to expedite the process. The loading arm can handle up to 10 rounds of loose ammo, or ammo in a stripper clip, and the rounds are locked into the mag with a quick push. Spend more time shooting, and less time reloading.