I looked in Nosler #7 manual for these numbers - that one still has longer range tables - their #9 does not.
So, as mentioned above - 140 grain and 160 grain was really common for 6.5x55 - looks like Nosler's heaviest is / was 140 grain - Accubond and Partition and two others. Is three powders listed to take 140 grain over 2,750 fps at muzzle, so I will go with that - 140 grain bullet, Partition (B.C. = .490), at 2,750 fps at muzzle from 23" barrel. I did have some 160 grain Round Nose by Hornady - if you prefer that weight, can maybe still find some?
Interpolating from table on p. 813, 2,750 fps for bullet with that B.C., has 2,224 fps at 300 yards. A 140 grain bullet, at that speed, has 1538 or so foot pounds - interpolated from table on p. 840. I do know from the energy formula on the SAAMI website, that bullet construction does not enter into an "energy" calculation - is just bullet weight and speed that matter. So any bullet weighing 140 grains and going 2,224 fps will have that much energy - is the Nosler sales pitch and my own experience that the Partition will let you get penetration that normal "cup and core" bullets will not. Accubonds have even higher B.C., so will have more foot pounds at 300 yards, then will the Partitions - I have no experience with Accubonds on game, but have heard and read that they perform very similar to Partition.
I guess would be up to you to compare that with 270 Win or whatever. Try to keep your comparisons as much "apples to apples" as you can. Around here, many moose hunters would opt for 150 grain or 160 grain for their 270 Win - for various reasons - although no doubt a bazillion moose and elk have been taken with 130 grain 270 Win.
I suspect that hitting a shoulder joint or not; hitting a rib or going in between ribs; a moose shot angling away versus fully broadside - will often have different results - and a lot of us will have experience of only one or two successful shots in our lifetime, so far - could have been lucky, or could have been "good" - personally, I will take "lucky" over "good" most days, any more...
I do know a local guy who takes EVERYTHING with his 16 1/2" barrel 243 Win - a Ruger Compact - coyotes, grey wolves, deer and moose - would be next to impossible to explain to him that his cartridge is not adequate, for what he kills. His sons use 7mm Weatherby Mag and a 28 Nosler - the old guy does not think he needs those boomers for what he does. I suspect he fits in to category "good". He has had too many dead things to be just "lucky" - we have eaten many pounds of deer and moose meat from him.