now I'm big on the 6.5-06 as I've often said in my posts, but not so big on the 6.5-06AI. But if you have a 6.5-06 Ackley improved, you can do just about any chamber from the .260 improved (Ackley never did anything with the 260 as it didn't exist). The taper per inch is the same, and they all come out of the 57mm Mauser family in one form or another. Some are stretched and others are simply shortened. You simply ream to the proper headspace.
The nice thing about doing a .260 improved is that when you out grow it, you can rechamber it with the same reamer. I gave as many options as I could readily think of.
* the 6.5x55AI is an over achiever, and will get you very close to 3000fps with a 140 grain bullet. Have never met a 6.5x55 shooter that wasn't in love with the round
* the 6.5x57AI is basically similar to the .257AI, and once again an once again an achiever. It will comfortably shoot 140's at 3000fps. Plus cases for these are easy to do.
* the 6.5-06 is also a great round, but really is less than 100fps faster than the above two rounds on it's best day. That's not great for a case that's almost a quarter inch longer, and tells us that we've about reached the max the .264 bore can handle.
* the 6.5WSM case is another one of those over achievers. It should come in as an overbore cartridge, but doesn't act that way. 3200+fps is the norm with a 140 grain bullet. This one fire forms very well with very little case shrinkage. A heavy load of Magpro should make this round a killer (probably close to 3300fps with the 140 grain bullet).
The oft mentioned .260AI will gain about 100fps at best, unless your into 70K psi loads. The generic .260 case is already considered to be an "improved" design from the start. (right from P.O. Ackley himself referring to the .308 case design)
Think before you cut metal, as you can't put it back
gary
