Re: 300 RUM and 180 gr. accubonds
I have done load development on a bunch of 300 ultras and they all liked 180 btips or 180 accubonds with anywhere between 94.5 to 96.5 grains of RL25 and a FED215gm primer. Usually, the velo will be 3300-3400 with standard deviations running 6-10 fps! 1/2" groups can also be expected.
A buddy of mine has a 300 ultra on a full NESIKA BAY rifle with a 30" barrel. Another friend of mine has a 700 remmy bdl same caliber. One day last fall, we took both guns to the range and chronoed one box of factory ammo. The 26" barrel spit out 3215 average and the 30" was clocking 3350! Four inches made those wimpy factory loads shoot like my HOT handloads!
P.s. All data read from an Oehler 35 ten feet from the muzzle. Temp was 55 degrees and overcast skies.
If it's not far, it's boring.