I can give you several empirical examples, successful and otherwise. Raw data, as always, is subject to individual interpretation and opinion. The following info assumes a modern steel high-strength barrel of 4140 or similar.

According to urban legend, Ackley said that the minimum wall thickness should be at least 0.125". IMO this is too little for the chamber area and I personally use a 0.175" minimum.

The Martini Cadet (0.750"-14tpi) has proven safe with 50K loads and the 0.375" case head of the 223 Rem. It's also safe with 40K loads and the 0.420" 30-30 or 225 Win case head, but the 50K factory loads of the 225 Win will cause problems.

The Win high wall (0.935"-16tpi) and the Sharps 1878 Borchardt (0.945"-16tpi) are both quite safe with 0.470" case heads & 50K loads, and FWIW I myself have built & shot a belted magnum on this size barrel shank. But I'm a hot-rodder at heart(grin).
HTH, regards, Joe

Last edited by J.D.Steele; 06/21/11 09:01 AM.

You can lead a man to logic but you can't make him think. NRA Life since 1976. God bless America!