Quote Originally Posted by bombdoc View Post
The "Quadrefoil" mark - a sort of four bladed propeller is the NATO Interoperability mark. Ammunition bearing this mark is supposed to be able to safely fire in guns conforming to the standard.
Is this mark found on the ammunition itself, or only on the packaging? It sounds familiar but I can't recall ever seeing any ammunition with this mark. Plenty with the circle-in-cross though.

Thanks for all the other good information!