Tektite’s Mag-Pump is a magazine loader for STANAG M4/AR-15 magazines, capable of loading both .223/5.56 and .300 BLK rounds. The hopper holds up to 60 rounds at a time, and the internal mechanism of the loader auto orients the rounds as they’re loaded so they go correctly into the magazine. Additionally, the Mag-Pump is quick to take down, and easily fits into a .50 cal ammo can for storage and transport.
Unfortunately, the clear polymer model seen above exists purely for demonstration purposes, and isn’t for sale.