I picked up a case of MFS .223 55 Grain zinc plated FMJ a while back and finally was able to test it in my gas piston AR. I was only able to put 40 rounds through though. Unfortunately one of the mags had some really old Wolf (old black box) FMJ. I should have left that stuff at home as it's underpowered and gave me nothing but stuck cases in the past. Well, sure enough, it performed the same way this time. After one round I had a stuck case and I forgot to take along my cleaning rod to extract it! Aghhhh!
The MFS seemed to work really well. The guy I bought it from at the gun show compared it to Silver Bear. Have you guys had any luck with MFS zinc plated .223?