Took two deer, one large doe, one button buck, with my .450 Bushmaster this season so after all the trouble I had with it in 2018 and 2019, I am calling the rifle redeemed... probationally.
Used factory loaded Hornady Black ammo with a Lancer AWM-5 magazine with a Tromix follower. It's a Bushmaster upper with a 20 inch barrel. I think I whined about all my feeding and ejection issue here a couple of times. Seemed to be ammo specific.. basically anything other than Hornady Black, and my reloads. And I had trouble with Hornady too. I tried many things, some which which (the magazine) helped significantly. I'm not sure how to attribute the ultimate success beyond the magazine except my attributing it to the gun breaking in and being run wetter than I normally run an AR. Sloppy wet by my standards (which go back to the U.S. Army).
Was in a blind on my own property shooting across an open field. On shot was 213 yards and the other at 225. I used a 3-9 Bushnell Banner scope. One shot was a perfectly placed lung shot, and it dropped immediately. The other was a little farther back than optimal and that animal did not react, calmly stepping into the woods. I thought that was a clean miss but a couple of minutes later it stepped back out in obvious, wobbly distress and soon dropped. That was the big doe and the bullet went thru in the liver area and went all the way thru and out the opposite side. Looked for the bullet in the buck and found only a shard of jacket. Didn't look too hard because by the time I had the deer in an area where I could fild dress it, it was dark and butt cold.
Anyway, I would not have tried those shots with my slug gun and my hold was just over the top of the deer (gun sighted at 100 yards).