Re: DPMS 260
I have exact same upper.
123 Amax seated to 2.800 +/- 0.002" (mag length)
45.4gr IMR4350
Win 243 Brass necked up, trimmed, chamfered, etc.
CCI Large Rifle Primers
This is a very stout load, back it down to 44.0gr and work up in 0.3gr increments. As I mentioned recently it's a consistently sub MOA shooter.
My next detailed load development is going to be 130 JLK's and H4350