I think the only Remington ammo I've tried that wasn't underpowered was their 125 gr JSP 357 mag and 180 gr JSP 44 mag.
If you waste enough time checking ammo velocity over a chrony you will see just how bad some of the stuff out there is.
Most of the "m193/m855 " put out is crap. IMI and PPU had some good numbers when I was playing with the chrony.
My ARs function on just about anything.