When the AR15 system was first introduced to and fielded by the US Military in the 1960s, the manual of arms for an infantryman was significantly different than what currently exists today. To charge the rifle the shooter released their hand from a firing grip, grabbed each side of the charging handle with the thumb and forefinger or the first two fingers , (while applying pressure to the latch) pulled the charging handle all the way to the rear, and then released it to charge the weapon.