I've shot tons of it through my ARs, a bushmaster 16" and a bushmaster 20" and had no problems. There used to be a problem with older wolf having waterproofing sealant around the neck of the case that supposedly melted and could gum up an AR, but newer wolf does not have this sealand. There is red lacquer on the casing bottom, but it will not melt.

Some guys have problems and more guys have "heard" about problems. I bought a case right off the back and it worked fine, if you are really nervous buy a couple of boxes at the gunstore or off of one the places that sells ammo by the box, like Sportsmansguide, and see how it goes. I and my buddy have shot many thousands of rounds of Wolf through our Bushmasters with no problems. It's only play ammo and it's funny smelling, but at 2/3-1/2 the price of real ammo it's fine for play ammo in my experience.