6.5 WSM and 264 WM


January 19, 2010, 03:41 PM
I'm currently building and .264 Win Mag (26" BBL). Ive always had this thing for the cartridge. Ive noticed alot of buzz around the WSM series of cartridges and wildcat versions of them. Alot of folk say that the WSM's can't actually match velocities that the regular magnums produce. When comparing the 6.5 WSM to the .264 I ran into what seemed to be obvious differences. The 6.5 WSM has slightly less case capacity. The 6.5 WSM has a shorter neck therefore the bullet would seat deeper furthur reducing case capacity. Maybe theres something I missed, I can't see how the WSM could actually match my 264. Anyone care to fill me in.

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January 19, 2010, 03:54 PM
Case capacity will win out when all other things are held equal.

The other thing to consider is that you can build a WSM on a regular length action and seat the bullets out such that they do not take up case space.

January 19, 2010, 03:58 PM
SAAMI MAX pressure for the .264 Mag is 64,000 PSI.
I believe it is 65,000 for the Whizzem series.


January 19, 2010, 04:42 PM
With my MRC 1999 / 26" Lilja 9 twist what would be limiting me from loading to 65000 PSI seeing an identical rifle in 6.5 WSM could be loaded to that pressure?

January 19, 2010, 04:49 PM
The brass case.

The Whizzem cases are very thick compared to any other caliber I can think of.


January 19, 2010, 04:53 PM
I was leary of rebated cases in a CRF action. I had the chance to shoot a Model 70 in 300 WSM and it had a hard time chambing one round. Out of five rounds I fired that sort of surprised me. Secondly is higher chamber pressure going to result in added velocity? I seems sort of obvious though I learn new things every day.

January 19, 2010, 08:01 PM
I have a 270 WSM and out of the 100+ rounds fired through it, I have never had any feed problems. I think the 6.5 WSM would be a good round, it should give close to the 264 Win with less powder. If you want to throw heavy bullets into the mix, then you'd be better off not with the 264, but the 7mm Rem mag.

I have been looking into a 25WSM(25-270WSM) myself, a 257 Roy with out the belt. The same can be said of the 6.5 WSM, a 264 without the belt.

Jimmy K

January 19, 2010, 08:56 PM
I have some (very limited) experience in head to head chronograph results between short & belted magnums. My experience between the two is only with 7s & .30s.
If the bullet weight is in the low to mid range for caliber,(160s & 140s for 7, & 165s are as heavy as I've tried in .30s) there doesn't seem to be much appreciable difference.
A slight advantage does go to the belted case, though.
I've not experimented with "longer" bullets, but it certainly stands to reason that the "belted" advantage would only increase.
Though I've never(yet) owned a short mag,there is no doubt that they are here to stay.

January 19, 2010, 09:30 PM
The longer 6.5mm bullets were really my worry. I guess im greedy when it comes to squeezing every last drop of velocity out. Ive loaded for the 7mm rem mag. I could only get 140's to move marginally faster (50 fps) than the 264 im messing with now. The 6.5mm bullets seem to be my next fixation. Ive attempted to find a spot between really overbore and velocity, that how I ended up at the 264. The better sd's and bc's of the 6.5 bullets outweighs any velocity gains that 270 and 7mm rounds offer. Ive got a .30-06 thats maxxed out on a diet of rl-22, it does all the <300 yard work. Maybe Ill break down and buy a WSM some day. Thanks guys

January 19, 2010, 10:42 PM
What about 6.5-284 Norma? Granted it works better in a long action or a Savage "short" action so you can load longer, but it has similar case capacity to the .264 WM.

10 Spot Terminator
January 19, 2010, 11:32 PM
Having owned and loaded for both an original Winchester model 70 .264 Win. Mag Westerner and a circa 1910 Carl gustaff 6.5x55 swede I am more than just a bit fond of the 6.5 cal. performance and potential . With all of the new premium performance bullets available the ceiling just keeps being raised . I have read pretty much every feature article on a variety of old and new 6.5 cal wonder cartridges including Lazzeroni, the 6.5 mach IV, 6.5-284, 6.5-06, and a dozen or more others . If I were to pick just one of newbies out there that fits some where between the 6.5x55 and the over the top Lazzeroni it would have to be the 6.5 STW ... This one is what most .264 Win Mag owners including me wish they could get their 140 gr. bullets to do and that is fly at 3,300 fps. flat and true over vast exspances of Western territory and drop majestic big game animals in their tracks . This one is built on the 8mm Mag case, has the perfect case capacity to be filled with the slower burning powders required to get these bullets to perform and with the longer than standard Barnes TSX bullets in 120 gr. I expect 3,400 fps would be possible without exceeding the pressure envelope . How many of you just got your 6.5 interest peaked ??? 10 SPOT

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