I've heard that steel cased .223 ammo such as wolf or tula is bad for ar's in particular. I've shot it but not quite enough to have the knowledge on how it could be bad. The bulk of my ammo is tula and wolf so I don't really want to have to switch over but I also don't want to destroy my gun. I also use Tula ammo for my xd and 1911 an it has seemed to function fine.