Too funny.
Let's see here, even with your figures, it takes 650 yds. for the 6.5 bullet to catch the .270 bullet. Right. We do our killing at 650 plus yards, not the usual ranges. - Didn't say anything about killing at 650 yards - the poster I was responding to made a blanket statement that a smaller cartridge couldn't catch a larger cartridge. That premise is not true as a blanket statement, as I showed. Beyond that, the .260 Rem has an advantage in wind drift at any distance where wind would make a difference. As has been written on the Campfire many times - it is a lot easier to compensate for trajectory than it is for wind drift with the variable wind speeds and directions (i.e., you have more margin for error with a bullet that drifts less in the wind).
Second, you "cherry picked the bullets. - False. Berger has some of the most aerodynamic bullets on the market, and that makes for a good comparison. You can choose a 130 Accubond for both .277" and 6.5 mm if that floats your boat, and the results will be similar. Cherry picking would compare a lead tipped Walmart .270 factory load to a .260 handload.
The .270 can throw a 160 gr. bullet as fast as the .260 throws a 130 gr. - Doesn't matter - not relevant to the blanket statement the other poster made.
Then there is the little matter of pressure. This is where the "my little round is as good as your big round" sorts kinda sweep this issue under the table. I've seen lots of data that says the .270, at the same pressures pushes it's bullets significantly faster than the .260. When it first came out, Remington tried this argument. Until somebody pointed out their ammo didn't perform like they claimed. - What does "book loads" mean? Apparently you didn't even look at the muzzle velocities I posted.
Last of all, you are assuming those BC's are accurate, and hold steady throughout the velocity range. Of which neither is often the case. - Apparently you don't know much about Berger bullets. The BCs listed by Berger are as accurate as any published because they have been diligently field tested (google Bryan Litz). Yes, BCs change as velocity does, but it is doubtful that the BCs change much differently between the .277" and .264" bullets I listed at the ranges I listed. If you want to go to that level, the 6.5mm bullet might catch up to the .277" bullet a little faster since the .277" bullet bleeds velocity considerably faster (possibly leading to more variation in BC for the .277" bullet that experiences a wider range of velocity).
You can believe what you want, but the data bears out differently than your preconceived notions.
