GunTruck50,
Based on actual results from the 150-grain Partition, in a number of rifles, I sincerely doubt QL's prediction of 60.2 grains of RL-26 would get anywhere near 3100 fps with a 140 AccuBond. Most rifles require right around 60 grains to get 3000 with 150 Partitions, and Partitions result in more velocity than most bullets (including AccuBonds) with the same powder charges, due to producing more pressure than most other bullets, because of their construction.
In my own .270's 22-inch barrel, 60.5 grains of RL-26 gets right around 3000 fps with the 150 Partition--which seems to be pretty typical of 22-inch barrels. Probably the same load in a 24-inch barrel would get around 3050 to 3075 fps, though Alliant lists 3022 from a 24-inch barrel with 60.8 grains of 26 and the 150 Partition.
Generally it requires a little MORE of the same powder for lighter bullets just to match the velocity of heavier bullets, and quite a bit more to exceed it. In my rifle I eventually worked up to 62.0 grains of RL-26 with 150's, which got right around 3100 fps, but even though there weren't any "pressure signs," pressures in my rifle are obviously above Alliant's pressure-tested results. This is why I use 60.5 grains.
A little calculation, using some simple formulas and actual result with 150 Partitions, indicates it would probably require at least 63 grains of RL-26 to get 3100 fps, and maybe more. I just tried various charges of 26 in a Winchester .270 case fired in my rifle. Drizzling 63 grains slowly, while tapping the case to settle the powder, resulted in the charge filling the case to just above the bottom of the neck, and 65 grains filled it more than halfway up the neck. You could seat a 140 on top of that charge, but it might get pushed forward by the compressed powder. (Filling the case to the very top resulted in a charge of about 69.5 grains.) This is in an unsized case. A FL resized case, or a heavier brand of brass, wouldn't hold as much.
I dunno what velocities RL-26 might result in with 140's in the .270. Haven't tried it, mostly because I'm happy with 3000 fps with 150's. But based on Alliant's data, and results with 150's from several rifle, I sincerely doubt 60.2 grains is going to get 3100 from a 24" barrel, despite what QL predicts.
