For over ten years I've used CMMG (0.8 oz.) and Ciener (1.0 oz.) ABWs in conversion units with barrels from 10.5" to 20" - some suppressed, most not; and in addition, for over two years in dedicated uppers with 4.5" bbl. - some suppressed, most not, and 9" bbl., not suppressed. Shot premium and crap ammo and stuff in between - standard and high velocity. Don't have a forward locator (aka "pressure plug"). My M16 has all standard mil spec FCG parts so I can readily shoot 5.56, 9mm, or .45 ACP.
I've seen several threads on various websites over the years on people trying heavier ABWs to reduce ROF; and getting reliable operation with a variety of ammo and/or set ups was always an issue. As long as I kept things clean, I've had reliable operation. I'll pass.
MHO, YMMV, etc. Be well.