I am wanting to take a stock stainless Ruger Hawkeye in 30-06 caliber and rebore to 338. Making 338-06. The stock barrel thickness is .305 in the lands at the muzzle. Is .250 the minimum wall thickness a standard in determining safe operating tolerances? If so, I should have enough metal to do the job without rebarreling.

Thanks, Dirk

When I had a .270 WCF rebored to .30-06 by Danny Peterson, he said that for rounds such as the .30-06 he considered 0.100 to be the absolute minimum wall thickness for a rebore, with thicker preferred for higher pressure rounds.

A gunsmith once told me 0.125" was a safe minimum wall thickness.
George

All depends upon where you measure from (grin).

Urban legend has it that P.O.Ackley said that 0.125" was the minimum wall thickness AT THE CHAMBER WALL.

I personally consider this to be too thin in most cases, and much prefer a thickness of 0.170" or more AT THE CHAMBER END. I base this opinion upon the performance of the Martini Cadet with various higher-pressure cartridges combined with the Cadet's 0.750" major thread diameter at the chamber.

The Cadet is known to suffer bulged chambers when chambered for such cartridges as the 225 Winchester with its base diameter of 0.420". Therefore the wall thickness of the bulged Cadet chambers is: the major thread diameter of 0.750" minus the case head diameter of 0.420", leaving 0.330"/2 as the failure node for the barrel wall thickness at the 225's pressure level of 50K+ psi.

0.330"/2 = 0.165" was/is the failure node for this application, at a pressure level exceeding 50K psi. I repeat, at a pressure level somewhat exceeding 50K psi!

Of course the wall thickness at the muzzle can be almost anything, even down to a thickness of less than 0.050" at the muzzle in many cases, due to the much lower pressure at that point.

Bottom line is that your rebore will be fine, except for the added recoil from the heavier bullets.
Regards, Joe

Thanks guys, I do remember Danny Peterson tell me he liked at least .100 at the muzzle.

Elmer Spurger and his partner Bill, Gunsmiths in GJ Coloado, 1960s use to put out some pencil thin muzzles. In all the time I hung out in their shop I never heard a complaint. They never, however got fancy with the metal around the chamber. roger

.2" at the chamber is my minumum rule. I had a reloading mishap once that produced pressure high enough to have brass flow of about .05" at the rim. The action held, and the chamber buldged, but didn't come apart. Pressure had to be well over 100k psi.