Well let me chime in here, hopefully the "6.5ers" are not too harsh here. I have been going through the same dilemma for about two or three months now!!While looking at the various load data from the various reloading manuals, it is IMPORTANT to look at the barrel lengths for the specific load data that you are looking at and making a cartridge determination and selection from. Even the same manuals will give data using a 24 inch barrel on one bullet weight and a 26 inch barrel on other weight bullets. There is a lot of data to look over, however it is not all the same due to the barrel lengths. I hope that I am not being too basic here, however giving my two cents worth; and, hopefully helping make a decision. I have looked up and down at the 6.5 data as well as the 7mm data. With all the excitement about the 6.5s, I have taken a very close look at the .270 Winchester as a common-sense approach to a long range rifle for my hunting purposes. I have two Ruger 77, tang safety, .270 rifles in my gun safe, if I were to start from scratch I would be building a .270WSM as I find that cartridge to be the best choice for the .270s. I thought about a .270 AI, however the load data is a bit sparse and according to Ackley the .270 Winchester is about as efficient in that barrel diameter. I also like the .280AI, however with the exception of the ability to use heavier bullets, I really do not see a great advantage to the caliber. I suggest that you compare all of the 6.5 calibers of the same bullet weight at the .270 Winchester round, and no matter what you will find that you are within 200fps in either direction. And...if you choose to build a .270WSM, you probably will come out on top or equal to the NOSLER super calibers. When looking at ballistic coefficients for the .277 130 grain you're looking at .459 in the Nosler and for the 150 gr Accubond long range a bullet coefficient of .625. Again make your comparisons, however remember it is important to remember barrel length for your comparison data. All of the reload data that I have read for the Nosler 26 and 28 are out of 26 inch barrels, where the only data that I can find in a manual for the .270 are out of 24 inch barrels. Good luck with your build and enjoy the fun when it is done.