Same ammo both instances. Federal M193 and IMI 77gr. The ammo pressure wasn't the issue, per se, it was the closed down gas port. I thought I may have run some BH Blue Box (which is .223), but I looked through my shot log and it shows I never shot any .223 with it. I had shot some Wolf Gold through it. I'm really not sure what that ammo is supposed to be, so do with that info what you will.