[quote

Personally have a .458 also and do NOT have a problem reaching 2200 fps with 500 gr bullets..

Ripp

Couldn't have said it better myself!

It's also true about the "spill" problem. A former employee of Winchester, who was involved in identifying and solving the problem (after several years!)has revealed that in writing when there was no chance of repercussions from Winchester since they no longer exist as a company... (in name only they exist).

It's also NOT true that all companies used 30" test barrels! Few, if any, do that today. Mostly 26", or 24"... and in some situations it's 22".

True, the CUP method was flawed... and it has taken too many years to figure out an equivalent pressure in PSI, or even what 53,000 CUP represented in PSI (piezo). Today, it's something like 62, 500 psi. That's MAP (maximum average pressure) which means that an acceptable load would have that average. That could be, for example, a low of 60,000 and a high of 65,000 psi. Loads for a Big Bore, like the 458WM, rarely vary more than 2000 to 3000 psi with the best modern powders. My loads vary less than that.

The problem for Winchester, in the early days, was the powder they used, plus the equipment that was not suited to loading ball powder. That's been resolved long ago. The best powders for the 458WM today are ball powders, which are greatly improved. The best powders for the 450s and 500s are AA2230, TAC and H335, all ball powders. 2200 fps can be efficiently achieved with any of them employing a 500gr in a 24" barrel, and in some cases a 22".

Bob

www.bigbores.ca