I know it's probably been talked about before but I have a 7 Mag that just doesn't thrill me. I have a 300 and a 375 that will do the heavy stuff better and as is, it doesn't deliver the accuracy to make it into a dedicated long range gun.

I've decided to rebarrel it, so what do I do? What's a good option for a magnum bolt face, long action M77? I would rather go smaller than larger as I really wouldn't use a 338 or 35 as much as I'd use a lighter long range gun.
What's the limit for usefulness, a 6-7mm Mag, a 25-7mmMag, a 6.5mm-7mmMag or ???

6.5x7rem mag is the 264 winchester
270x7rem is more or less a 270 weatherby mag (diff shoulder)
a 257x7rem is more or less a 257 weatherby mag (ibid)

i dont' recall a 6x7, and wouldn't do it due to the fact that it would just be a barrel burner

If you have a ruger 7mag long, Ihave a 257 wsm on a 1903 action...

wanna swap?

jeffe

Thanks Jeffe, but it is left handed and I've already had it pillar bedded and the trigger worked over so that's why I want to build rather than sell.

Jeffe, the 6x7mag is basically the pre-war H&H 244 Magnum so even it has been done. I've read that it isn't such a good idea even with today's powders, though. I think of the three I'd do the 257 WBY just for its' flexibility.

Harry,
you are prefectly right.. in fact, i am near to the point of running a 257 webby in my 257 wsm....

i think you can still find 140gr hornady bullets.. from time to time...

jeffe

Try a .264 Winchester Magnum, loaded ammo is available and reloaded with the 140gr. and 156gr. bullets, it's a real performer.

The 7mm Rem Mag necked down to 6mm with the case blown out & 40 degree shoulder is the 6mm Mach 4.

It pushes a 95gr projectile at 4095 fps.

About 1996 a friend of mine necked a 7Mag down to 6mm and blew it out to 35 degrees. Just for fun he turned the belts off of the cases and didn't cut the belt in the chamber. With a 28" 8 twist bbl. he got Berger 105's going so fast that they came apart in flight. The primer pockets got real loose real fast without the belt. He made new cases, with belt, and cut the belt in the chamber. Now he got some Sierra 107's and loaded them over R22 and got 3600 fps. We took it to New Mexico on a PD hunt and had many 800 yd. kills. Somewhere around 750 rds. the bbl.went south. All in all a lot of work went into what he already knew was an overbore, barrel eater. He named it the 6mmDJBMF.

My .240 Incinerator is basically a 6mm Atlas Improved (6mm-264). I've been shooting the round since it was designed in late '92 and it works well (though barrel life is very short). There's an article on my website that details the cartridge.

Lee Martin
www.singleactions.com

I looked at the 264 Win Mag and used Remington's ammo comparater on their website. Using the 140 grain coreloct bullets the 7mag outperforms the 264 Mag in all ways. It's weird, their 140 grain, 7 mm SP has a better BC than their 6.5 and the 7 mag starts it at over 130 fps faster which translates into much better downrange ballistics.

I'm sure that other maker's bullets and handloaded ammo would change this but is it a big enough difference to make a serious ballistic advantage?

Just to throw out a few numbers for your evaluation, I have a custom 264 Win and am getting 3278fps with a Sierra 140. Close to 3500fps with a Nosler 120 Ballistic Tip. The rifle is a Remington 700 with Krieger #5 crowned at 26".

Thanks, Remington lists their factory 140 grain load at just over 3000 fps, your numbers make it much more interesting.

Yeah, factory ammo in the .264 isn't loaded too hot, I know of one 24" .264 hitting 3250fps with 140gr. Noslers and 3120fps with 156gr. Normas. Typically, a 140gr. .264 bullet will have a much higher ballistic coefficient and sectional density than a 140gr. .284 bullet, and should therefore have flatter trajectory, more retained energy, and deeper penetration.

You have two good choices by uing a 6.5 Rem Mag case which is about 06 capacity. You can neck this case down to 25 and you are looking at a 25-06. Brass is easey to make from 7mm Rem Mag.

Fjold, the 264 doesn't really wake up until the barrel gets to 26" and another 2" makes way more difference than one would think. With a 28-30" barrel it is a completly different round than it is in factory guns.
Another issue is the chamber. If you do some searches you might find more info but the original factory throat was short and designed for two-diameter bullets. The front part just behind the ogive was more or less bore-diameter and the rear was grove-diameter. This let the Winchester two-diameter factory bullets seat out farther for more powder room. Of course, no one makes two-diameter bullets anymore so convetional 6.5 bullets seat deep in a factory spec throat. That's another reason besides barrel length why it can be hard to reach older factory velocities with modern bullets and handloads.
All you need is a chamber reamer with longer throat dimensions and you get back the powder space and all the performance the round is capable of.