I can't believe there would be one spec of a difference between calibers on a "in the vital area" hit. Or, for that matter a gutshot! To me the .257 wins for popularity with resale and more bullet availability. BUT these are my opinions and you are writing the check!!--Good Luck--d kraky
I would agree on your response if the buyer was only shooting factory loads, but for the reloader, the possibilities are there for better long range performance from the .264............with the right twist rate and barrel length.
Kraky if you had to be hit by the lightweight or heavyweight champ of the world, which would you choose? They can both knock you out and the pain would hurt the same. It may just take you longer to recover from from the hit.
I've had them both and the 264 is the winner in this shootout.
There are MUCH better bullets with higher BCs available for the 6.5 (264) then the 257 if you are a handloader.
Being as this is a longrange forum and I presume most of you are are longrange hunters, I would much rather use a 140 to 155 gr high BC bullet compared to the little 100 gr (with low BC) that is popular for the 25 caliber rifles. There are a bit heavier 25s but, not to many.
Ballisticly the 264 wins, no doubt about it.
Run the numbers on your ballistics programs and check the energy levels of both at all ranges.
264 WIN need a barrel over 26 inch , Winchester company have kill this good round by reduce lenght of the barrel from 26 to 24 inch ( short barrel fashion in the 70's ) by this way 264 win performance is just at th e level of the 270 win but with 27 inch minimum lenght 1 in 8 pitch 264 WIN is a winner .
I forgot to add, you will need an "8 twist" barrel in the 264 with the heavier bullets to make them perform well.
Don't go with a 9 or 10 twist like the factory did.
A 9 twist seems to only stabilize and accuratly shoot bullets with a weight "UP TO 129 or 130 gr."
8 twist in the magnum 6.5s will perform extremely well.
The first time I saw a 200 score on the 1000 yard line, it was shot with a 26" 1:8.5" twist 264 winmag with a long throat. He used 155gr SMK's and shot a 200 - 11X. Since then, I've seen three more 200 scores shot using 6.5x284's and 142SMK's, two of them just last Sunday. With the 142SMK, the 264winmag easily got 2950fps without any pressure, and would be my choice hands down.
If you only want to shoot bullets up to 120 to 130 grs (max) it would.
The better bullets start at 140 gr and go UP from there.
The 9 and 10 twists in the factory barrels do not stabilize the heavier bullets well. The accuracy is terrable in any I have seen except for lower weight bullets shot in them.
You need an "8 twist" in the 6.5 for the 140 to 155gr bullets for longrange hunting/shooting. That twist seems to work the best.
You can always rebarrel later after you shoot the lighter bullets in the factory rifle you mentioned?
Im a fan of the 257. Ive shot 5 bull elk, ? cow elk, lots of mule deer and 3 whitetails( barnes bullet went through the buck and killed the doe 15yds behind him) a 22 with good shot placement kills just as much.
264=better bc bullets
257=higher velocities flatter shooting