26 Nosler claims: do you believe them?

[taylorce1]

Extreme Spread or ES is not the main thing to worry about. There is usually an accuracy node and that a rifle will shoot in for speed and it could cover more than 100 fps. The main thing is to get your Standard Deviation or SD down low as possible, and I'd consider anything in the 20 or less rang pretty darn good for 20 rounds of factory ammunition.

I'm not a web site guru and don't know why the ammunition isn't listed yet. However, they have it listed under new products.

[GeauxTide]

When is comes to rifle cartridge development and expansion ratio. Grab a copy of Ackley's Rifles and Cartridges. Until the powder companies develop powder treatments that can produce greater velocities at acceptable pressures, over bore cartridges will remain a riddle wrapped in a mystery inside an enigma.

[reynolds357]

Overbore is not really a mystery at all. I do not know the physics formulas for it, but burn more of a given powder, get more velocity. The larger the case volume, the more powder you can burn without blowing the rifle up. As long as one understands that the more over bore you go, the more your returns diminish, its not all that complicated. A .50 BMG necked down to .30 Cal is not much faster than a .30-378 even though it burns twice the powder. One must also keep in mind that if you can work it out to where it does not mess up your accuracy, freebore is the same as extra case capacity. Thats how I make my .30 cal wildcat beat a .30-378WBY even though it has 4% less case capacity than the WBY. WBY is using freebore, I am using a ridiculous amount of freebore.

[Bart B.]

Reynolds says:

I doubt it is faster than the win mag. The Win mag is one of the most underloaded cartridges I have ever seen. In many cases, it capable of 12 to 15% more velocity than published data.

A .264 Win Mag can shoot 140-gr. bullets out at 3467 fps at SAAMI spec max avg pressure of 64,000 psi? That's 15% more velocity than industry standards.

Why is it underloaded when SAAMI specs state that bullet and psi numbers are for 3015 fps as shown on page 5 in:

http://www.saami.org/specifications_...essure_CfR.pdf

There is no official physics formula I know of for what overbore capacity is. My own emperically devloped one is overbore cartridges burn more powder in grains than the bore's cross sectional area in square millimeters is. A 30 caliber bore has about 45 square millimeters cross sectional area so 45 grains of powder is bore capacity for 30 caliber. 30 caliber cartridges using more than 45 grains of powder are called 'overbore capacity' ones. All cartridge right at bore capacity seem to get about 3000 rounds of tack-drivin' accuracy; .222 Rem., 6PPC and .308 Win. are examples. One guy even improved on my formula by adding powder burn intensity values; hotter powders reduce barrel life, cooler ones increase it.

[Roadkill2228]

I second the refutation Bart makes. The .264 win mag will be crazy overpressure to get those numbers. Look at it another way; that's as fast as a 7mm ULTRA mag is able to push a 140 grain bullet. And there is no comparison between said rounds.

[pathdoc]

GeauxTide, powders have come a very long way since Ackley's day. Specifically there seems to have been a LOT of development at the slow end, which IIRC is what the relatively over-bore cartridges prefer to be fed.

[Bart B.]

Before ultraslow (extra-slow?) powders came about, none of the slowest ones back then were really great in the accuracy games. While they would push a given bullet out faster with the same peak pressure, the pressure curve was not too repeatable. Muzzle velocity spreads got bigger and accuracy wasn't as good as slower, middle range powders for the case size produced.

Overbore cartridges of decades gone by clustered bullets the closest together on target with upper mid range powders; fastest burning at the low end and slowest at the high end. Good examples are the .308 Norma Mag and .300 Win Mag with medium to heavy weight bullets. IMR4350 or the next slowest powder won the matches and set the records. IMR4831 and slower ones shot bullets faster and won all the races to the target but the real estate they landed in had more acreage.

If these new superformance (sp?) powders win a lot in accuracy games, then they'll have some credibility.

[Roadkill2228]

I have tried the superformance powder that is available to reloaders and I'm afraid to say its been very disappointing

[reynolds357]

Bart, the .264 Win mag is underloaded because I have gotten much, much, faster velocity out of it than published data. One of my actions is on its 4th barrel and has not blown up yet. Two actions are on second barrel and one action is about to be on its second barrel. Yet to blow any of them up. Granted my rifle I get the blistering velocities out of has a ridiculous amount of freebore, but the ones without the freebore can be loaded almost as hot as it can. I have a load with 85 grain bullet that runs over the chrono between 4040 and 4070 depending on temp. As far as brass voodo goes, it shows no pressure signs.

[waveslayer]

The issue is... it's a barrel burner. Go 6.5 SAUM!

[Brian Pfleuger]

Originally Posted by reynolds357

...has not blown up yet.

Of course, that's not really the standard.

I would ask, how many loads do you get before the primers start falling out?

Besides, generally speaking, what ever difference is between two cartridges when loaded at SAAMI max, there is very likely to still be if they are both loaded to the same level beyond SAAMI max, particularly when the cases are so similar as the 26 Nosler and the .264Win Mag.

[reynolds357]

It depends on how good or how bad the brass is. Back in the 80's when brass was actually good, I got 7 to 8 reloads on a piece of brass. Today, 4; then I switch to Wolf primers and get 2 more due to their over size.