The PAP M90 is chambered in the popular .556 round and will also shoot .223  both steel and brass cased ammo. There are 3 adjustable gas settings so you can quickly dial the rifle in to your ammo or muzzle device. As with all Zastava products the M90 is built like a tank featuring RPK style bulged trunnion and 1.5 mm thicker receiver. The hammer forged Zastava barrel is chrome lined to provide years of accurate shooting and range fun.