Many, many AR’s are, let alone some other auto loaders. Especially when new, because there are lots of sharp edges on inside moving components. I’ve built several AR’s that dented, left scratches & even gouged the brass. But I had a Cetme (HK G3), that just absolutely mangled the brass. The Delayed-Roller Blowback extraction was so violently forceful, it would literally rip the cases in half! The cases it didn’t, looked like a shirt that Freddy Kruger had his way with. It was fascinating. Luckily, 308 was like $0.10/round back then.

I’d shoot it awhile. Give it a few hundred rounds see if it starts smoothing some edges a bit.