Home Forums Hunting & Shooting Ask The Gunwriters 6.5 SAUM Hype

I noticed on snipers hide the new big caliber is the 6.5 Saum. They tout the barrel life that they are getting from this caliber. I noticed that they are keeping the pressures down around 58000. My question to the gun writers is won't you get good barrel life from any caliber if you keep the pressures down.

I'm not a gunwriter. But the notable thing about this cartridge is the performance they're getting (high velocities with slick bullets) coupled with the barrel life, not the barrel life by itself.

Yea but 3100ft/sec with a 140gr bullet isn't really that fast.

IIRC George won a pretty big comp shooting one with a round count over 4000.

That's competition accuracy at a very high round count and a single set back. Shooting informally and hunting, guessing 1 barrel is all a guy would ever need.

The major factor in barrel life is heat, not pressure. I doubt there's much difference between 58,000 and 65,000 psi, but the amount of powder burned directly affects the amount of heat produced. The SAUM case has a little more powder room than the .284 case, but not a vast amount.

Shoulder shape and neck length also have considerable effect, and the sharp shoulder and moderately long neck probably help.

Like I said, it's the combination of performance and barrel life.

And by the way, 6.5 SAUM is not a caliber.

It's about heat applied to the throat.

You can decrease heat at least a couple ways: by decreasing bullet throat dwell by using bullets (usually lighter) that have less bearing surface to get started;
or you can use a lubricant like moly to help them get started. Either way decreases the amount of time the throat is exposed to heat and therefore the heat absorption.

You can also decrease heat by using less powder or by using cooler burning powder. Winchester used to advertise this feature. This factor is taken into account by this http://www.accurateshooter.com/technical-articles/excel-formula-predicts-useful-barrel-life/ barrel life predictor and is a attribute listed in Quickload.

Some people say a longer neck helps barrel life too. I don't know, but I can imagine how it might shield the throat from the hottest flames.

A longer neck does increase barrel life, because erosion is greatest right in front of the case body. A longer neck protects more of the throat. A sharper shoulder also helps, because the worst "blast" of the hot gas is concentrated inside the neck, rather than in front of of it.

The military has done a lot of research on erosion, which is where I found the above info--and many other interesting items.

IIRC using a larger than 'normal' case for a bore size and slower than 'normal' powder for increased barrel life was the reasoning behind the design of the 220 Howell. I haven't seen Ken post in a long time, but a search should pull up what he's posted in the past.

I'm afraid I'd have to step on the gas with that one. I can't imagine having all that horsepower and leave it on the table to save money on new barrels, at least for a hunting gun.

Competition I can understand.

I don't think 3100 with a 140 out of that case is leaving a lot on the table.

I bet that is right. 3100 is pretty quick with that case capacity.

Hopefully Pat will see this and offer his experiences. Barrel life and recoil of this round seem amazing.

Hey John, what do you think is the optimum neck length?

Sick fu*ker.
Laffin.

+1 on that one!!!! That just TOTALLY ain't right!

I've yet to see that definition of "set back".....

Set back in a BR gun is a thread or two.

Cutting off the tenon and then some, is a re-chamber......

Does the 5-6 grains more powder that the 264WM uses to reach the same velocity of the 6.5 Saum make it that much more of a barrel burner if everything else is equal, powder ,primers, bullets etc.

I think Remington beat those guys to the punch a long time ago with the 6.5 Remington Magnum.