What do you use?

So far, I’ve used various, but primarily Federal 55gr .223 FMJ. Would love to find some good alternatives. The pennies matter, though I’m not interested in anything that would cause damage to the gun or fail to cycle properly. If $0.28-0.30 per round is the best to expect, no worries.

I’d also love to hear recommendations for 77gr “practice” ammo. I’ve got good Black Hills stuff for when I want to get good precision practice or keep in mags for HD, but would love to find alternatives that would perform similarly for a lower price.