It is! And for better or worse, LEE is pretty much responsible for all the others. Maybe y'all have heard the term "whack-a-molie," but that's how I started out in 1986, and the LEE priming tool was definitely a "single-shot." I love to hate the AutoPrime, but since I don't plan to own a progressive press, and the original Safety Prime was a dog, I guess I'm stuck with it, and at least No 5. They work, and they'll work longer if you lube the internal contact points. I've used white lithium grease with some success until a buddy who shoots benchrest turned me on to a boot polish sold by Tractor Supply, with Beeswax as a case lube, I'm using it for my latest iteration of the AutoPrime. Might try the new version of the Safety Prime, but sure wish that LEE would give up their obsession for making hard wearing parts with inferior matl's.