The PP-19 Bizon is a Russian 9mm AK model using helical drum magazines, made in several calibers. It was taken into service in 1996, and has been making Western AKphiles drool ever since, because who wouldn't want a compact 9mm SMG with a 64-round capacity (64 rounds in 9x18 Mak; 53 rounds in 9x19 Parabellum).

Well, Stuff & Things recently released their "Stizon", which is a kit to let you mimic the Bizon on one of four different US 9mm AK platforms (PSA AKV, CAI NAK 9, CAI 9S, or KUSA KP9). It is a basically drop-in kit, replacing the handguard, muzzle brake, and magazine catch while leaving all the mechanic parts untouched. Two models of drum are available, one with a solid black casing and one with a transparent body.

I put a Stizon kit on my KUSA KP9, and I've got it out today for the monthly 2-Gun match. I'm shooting in outlaw PCC division as a way to have some fun with the new gun, so my scores aren't a fair comparison to other folks. I had a couple issues with the drum, which is honestly not a huge surprise - drum magazines (helical ones in particular) are notorious for working *most* of the time. The Bizon was in fact replaced in Russian military and police service after about a decade because of drum magazine issues - the replacement Vityaz is essentially the same gun with traditional box magazines.