Home Forums Hunting & Shooting Ask The Gunwriters 264WM vs 6.5PRC

Help me out, what am I missing. Why does the 264’s performance only just equal the PRC round? I would have thought with the additional case capacity, the 264WM should have had a significant performance gain. Thoughts?

See the recent thread 7mm RM vs .280 AI. Maybe similar issue.

Got a couple 264’s. The PRC sounds cool. There was a time not that long ago we had few 6.5’s, now one behind every bush!

PRC is new kid on the block. I would seriously consider getting one except I've been shooting a 264 for 50 years and have never found it wanting. I will enter raffles to win a PRC though. If I win one then . . . . . . . .

Marketing 101....

The original 140 gr bullets from both WW and Remington were dual diameter bullets. That's right back half to 1/3 of the bullet at groove dia., a short tapered section forward of the cannelure then the diameter was .257"which ran on top the lands. Which both rifle makers utilized a very short throat and held the coal to 3.34". Neither bullet was a real tackdriver either but atleast the throat allowed them to be seated out a bit. With modern full diameter full length 140's you have to deep seat them to accommodate the short throat which robs you of powder space. Put a short barrel on it and really fug it's potential. With a 700 and it's 3.6" box plus the judicious use of a throating reamer 140's+ the right slow burner powder would be more than a dream...mb

The original 140 gr bullets from both WW and Remington were dual diameter bullets. That's right back half to 1/3 of the bullet at groove dia., a short tapered section forward of the cannelure then the diameter was .257"which ran on top the lands. Which both rifle makers utilized a very short throat and held the coal to 3.34". Neither bullet was a real tackdriver either but atleast the throat allowed them to be seated out a bit. With modern full diameter full length 140's you have to deep seat them to accommodate the short throat which robs you of powder space. Put a short barrel on it and really fug it's potential. With a 700 and it's 3.6" box plus the judicious use of a throating reamer 140's+ the right slow burner powder would be more than a dream...mb

Bottom line is the 264 Win Mag like the 257 Wby is a highly overbore and needs a 26-inch barrel to increase its expansion ratio and get the most out of the powder volume and gas expansion. The PRC is less reliant on barrel length due to less powder usage and more uniform burn rate.

If one were to set up the 264 Win Mag long throated with a 26” barrel and use VLD bullet loadings you could better 3,200 fps with 140gr - 145gr class bullets. Starting a Berger 156 OL at 3,000 fps would be a wicked long range game getter.

The PRC only needs a 24” barrel to produce high velocity performance (shy of 3,000 fps with 140gr class bullets), but will not produce upper end speeds or better the use of heavier 6.5mm bullet performance than a 264 Win Mag. It is however a better carry rig for hunting purposes, especially alpine type, while the 264 Win Mag is a better long range bean field rig utilizing a 26-inch barrel delivering a heavier payload.

I think the .264 Winchester is good for a couple more hundred FPS with the same bullet.

The Hornady Match load in 6.5 PRC and the 147 ELDM lists velocity at 2910.

I’m shooting the 147 out of my .264 WM at 3090 and it’s in a lower velocity node, pretty tame

550 yard group on development day




The 139 Scenars went around 3225

Yup. That's what I'm doing as well.

Last elk camp turned out to be an all 6.5mm affair. Got to use a borrowed PRC on a cow elk. It was nice, but I'm not gonna go out and buy one.

If however, I win one, well, that's different...

I wore out one barrel on a Win 70 Classic in 264 mostly looking for 3200 fps with 140 gr partitions and spbts.

Early RL25 was a step in the wrong direction.

The feat can be achieved today with most rifles using new powders I did not have available.

But I am satisfied with 3300 fps with Magnum and a 130 accubond from the new 27 inch PacNor.

many cartridges like the 6.5 PRC do well for a while then all of a sudden they are obsolete no matter how good or bad that cartridge is. but the old 264 Win. mag. 30-06 and many others just keep on truck`n ahead. 10 years from now lets see if the 6.5 PRC is still around ?

Steve,

I suspect the 6.5 PRC will be around a lot longer than the .264, partly because the .264 keeps fading in popularity--and at its peak was never a popular as either the 7mm Remington or .300 Winchester Magnums.

This thread contains some good points, but also some common misconceptions. Let me start with the reason today's pressure-tested loading data for the 6.5 PRC and .264 Winchester shows very little difference in muzzle velocity:

1) NEW .264 data has been scarce for a long time now, because the cartridge never was that popular. When I bought my first one around 20 years ago--a genuine M70 Westerner--new data was even scarcer. Which is why I worked up loads with new powders using old-time methods, such as measuring case-head expansion--though my comparisons were a little more sophisticated. But I still managed to work up what were apparently "safe" loads at 3200+ fps with various 140-grain bullets. (If anybody wants to read this old article, it appeared in the February 2005 issue of Handloader.) Have continued to experiment with the .264 since then, in others rifles with various barrel lengths and rifling twists--most of which appeared in Chapter 30 of the first Big Book of Gun Gack.

The biggest long-time misconception that appeared in this thread is that seating bullets "longer" gains any significant amount of velocity. This is due to the 4-1 Rule, which is that any increase in powder capacity in cartridges of the same caliber results in about 1/4 as much velocity.

Let's say bullets in the .264 are seated 1/2" further out--which would be quite a stretch. This results in .127 cubic inch in extra powder capacity. The cubic capacity of the .264 case with a typical bullet seated is around 78-80 grains of water--which happens to weigh just about as much as modern smokeless rifle powder. The additional "powder room" added by such longer seating amounts to less than 1% more powder room--but let's call it 1%, to make things easy. 1/4 of 1% amounts to about 8 fps in additional potential velocity. Try to find that on the typical chronograph.

I just checked the maximum-velocity loads of the 6.5 PRC and .264 Winchester in three sources of newer, published, pressure-tested data, with bullets around 130 grains and 140 grains. The sources were Hodgdon, Hornady and Nosler, and the difference between muzzle velocities in the two rounds were indeed very small--and the SAAMI maximum average pressure is 64,000 PSI for the .264 and 65,000 for the 6.5 PRC--which is insignificant.

Instead, I believe the "sameness" of the results is due to three factors:

1) The barrel length is all mixed up. The Hodgdon data was shot with a 24" barrel in 6.5 PRC, and 26" in the .264--but the Nosler data as shot with a 26" 6.5 PRC barrel and a 24" .264 barrel, as was the Hornady data.

2) Since the .264 isn't very popular, companies tend to run their .264 pressure barrels longer before replacing them. As the barrel wears, eventually this results in lower pressures and velocities.

3) Since the .264 isn't very popular, there's no major reason for companies to try every new powder to determine the "best" powder--especially in new pressure barrels. They just want to provide "safe" data for the relatively few handloading hunters who still use the .264.

I'll additionally observe that the major difference between the .264 and the 6.5 PRC is the PRC was designed to use high-BC bullets--which don't need to be started as fast to provide similar down-range performance to .264, especially in the original M70 Westerners which had 1-9 twists, which wouldn't stabilize some of today's 6.5mm bullets.

My model 70 classic has a 1-9 twist and my daughters BACO stainless featherweight has a 1-9. What makes no sense Winchester used 1-8 twist barrels in the 6.5x55 classics and as we all know the 6.5 cm..

That is where I landed in terms of same same but different in terms of velocities and barrel lengths in the reloading manuals. The old 264wm seemed to have a bigger boiler room and wasn't getting any real world advantage over its newer sibling. I was wondering whether the 264wm had more in it given newer powders, much like the 270 has done with RL26 and 150 grain bullets.

Buddy has a 264Win Mag 1:8 Bartlein @ 26” on a M-70 loading 156EOL’s @ 3.335” & 2910fps via Magpro.

Just throwing out some more modern twist/projectile/powder data for the 264Win.

Ran a bunch of powder models on QL. R-33 and VV570 were the only 2 that theoretically were appreciably faster than Magpro, getting close to 3K FPS w/the 156’s.

With the 264 WM, I will mention a couple of things. First, this cartridge EATS barrel throats, but H1000 burns cool and will greatly enhance the barrel life as will N160.

Second, if/when you try R#25, expect the best accuracy, and lowest SD(sub 10 fps) with a Winchester Magnum primer, while a fed 215 will just blow the groups up with this powder!

Years ago, I shot a Winchester Model 70 out with 129g HOrnady sp with IMR 4831 before I learned how well H1000 performed with 139g Lapua's in a Rem 700.

When you have no experience with the 264 Win Mag caliber, it can seem to be particularly finicky to find a load for. If you follow the Kiss, Find Pressure, Rock On method, your success will be easy. Barrel life was almost used up developing loads on my Model 70(my ignorance), not so much on the Remington. When I did find a load with the 123g Lapua and 129g Hornady Sp, velocity was 3175, and I never used more than one shot on a deer or hog...never, under 300 yards was typical. A Brux 8T in this caliber would be my choice because they are slick as glass inside!

I had a friend and an uncle that used a .264 in the 70's and 80's and seemed to work well enough...no better than the .270 wcf I carried .
I also used a 25/06 alot at that time, the .264 diameter bullet didn't offer anything special.
A fast twist barrel doesn't offer me anything either, and the 6.5 PRC just seems unneccessary.
In the old days we carried wood and blue up into the highest basins, weight and a long tube just didn't seem to matter, these days Iike lighter more compact gear.
I carry a different .270 wcf now, lighter and shorter and higher performing than ever.
Rule #1 for me, a repeating rifle will not have a long tube and the wcf works ideally with a 22" barrel.
The 25/06, .264, 7mm magnums do not. My criteria at 65 years.
Can the 6.5 PRC thrive with a 22" barrel? I doubt it.

well then throw this in with the 6.5x284 which has set a lot of bench rest records , 6.5 x284 brass might be easier to find and /or neck down 284 brass than a 6.5 PRC ? yes i am a 257 Weatherby mag lover and now days this cartridge can compete in the hunting world yet . the one thing about the old 264 Win. mag. is if you have a Winchester model 70 pre-64 " which i have a couple " this old rifle cartridge in a PRE-64 will still work fine for hunting but it will always have way more resale value. yes the 6.5 PRC is right now the hot 6.5 cartridge so to speak " yes i did schooled a little by John " but for how long will this cartridge " 6.5 PRC " in a rifle be around or have much value in the future . or be the better 6.5 cartridge and maybe another caliber will be the new hot ballistic cartridge ? could be a 25 caliber ? seems the ammo - gun manufactures are always trying to find a way to figure out a new hot cartridge which is fine ,personally i wish they would bring back some old cartridges in a fine looking wood stock ? 6.5 Swede ,257 Roberts , 256 Newton , 250 Savage just a few examples , some us are tired of the small selection of rifle / cartridge selection available and seems all are plastic stocks now mostly ICK !

The 6.5 PRC does not depend on a 26" barrel to do well, with a 18" barrel and 139 gr. Scenar and R-26, the 6.5 PRC suppressed kills as well as any thing else i have used, on all types of big game, some bigger than the storied bullet proof Rocky Mountain Elk. if you haven't tried it don't knock it. Rio7