Not all mags are equal - Fort Scott Munitions Pack/Load .223 Remington 55 Grain Full Metal Jacket Range Brass Cased Centerfire Rifle Ammunition

First I tried this on a metal mag and was getting frustrated that it wouldn’t load. But when I tried it with a pmag, the rounds went in effortlessly.
Haven’t had a chance to test the ammo. Also the rounds can fall out the side if there is slack.