Anybody out there shooting an AR10 rifle in 260 Remington and if so what kind of successful loads are you using? I have an Armalite AR10 that I built a second upper in 260 and have been having trouble finding reliable loads for it.
I run a 6.5Creed, which is pretty close for load data, out of an AR-10.
I match the factory Hornady loading, 42.5gr H4350, 210 primer, 140gr AMAX and it runs good.
260s tend to run another 0.5-1gr so if you started around there you should be fine, I'd suspect some other problem than the load if you're in that ballpark already.
I have found black hills 139 Gr. to do very well in my DPMS lr260, which is very similar to your own gun. HSM also makes some really good .260 ammo, but it just dident suit the DPMS as well as black hills does.