My first CZ Hornet had a .224" breech but was .223" at the muzzle. It game no pressure signs using .224" bullets, but with the 45gr. Hornady SP's, it shot identically with .223 or .224" bullets. I used 13.8gr. Lil'Gun with those, for 3,150fps even IIRC. RP brass and pistol primers. Shot a coyote with one of those at 150yards. He was loping across the field. My rifle just happened to be on the bench. He dropped with a shot through both shoulders. We could only find the entrance hole after the farm owner's Rotty shook it around a bit.
Had a Rem. 788 in .44 Mag back in 1972. With Nosler Carbine loads, it shot into 1 1/2" at 100 yards, 2 1/2X scope. I don't remember case ejection problems. Only thing I shot with it, was a HUGE porcupine. Tasty.