Look at Western Powders/Ramshot's 5.56 data, it's pretty clear. They list charges for the 75gr Hornady BTHP a full grain higher than the 77 SMK with their four most appropriate powders; obviously those two bullets build pressure differently.
Yeah, I checked their website.......I don't use any of those powders though.
Maybe I'm light on my 75 Hornady loads
Unfortunately, there's not much data available for AR Comp.......but Alliant does list both the Hornady & the Sierra 69 & a heavier charge is listed for the Hornady bullet there just as a comparison so maybe there really is that much difference.
Sure would like to have a pizzeo system.
Maybe I'll check hardness on a few bullets, just for the helluvait.
MM
