This is from the hodgdon database, which includes data from IMR, Win, and Hodgdon powders. using the 140 Nosler Partition bullet for all 3 cartidges here are the fastest max loads.
7WSM 3161fps 63.2grs of IMR 4350@63,200psi
7SAUM 3217fps 62.0Cgrs of hybrid 100V@62,400psi
7mmRem 3138fps 63.0grs of hybrid 100V @59,800psi
here's another load for comparison;
7SAUM 3174fps 61.2grs of IMR 4350@62000 psi
The short mags are both loaded to higher pressures than the old 7Rem, not sure why. The 7SAUM comes out on top in this comparison.[/QUOTE
Sammi rates the 7mm Mag case at 61000 psi while the Short mag cases are rated at 65000 psi. As well the 7mm RM is prone to pressure spikes. The 7mmRM cases generally start out with 8-10 thou short of a Sammi Chamber, as they headspace on the belt. This causes about an equivalent case stretch, on first firing, which results in thinning of the case ahead of the belt. I have had incipient head separation, on second firing, trying to get 3000fps from 160 grain bullets using loads listed in the Speer #11 Manual(1987). In the Speer #12 manual (1994) they cut back the max loads by one full grain of powder. I wonder why?
A couple of years ago I witnessed a young fellow wondering why his new 7mmWSM had blown a primer clean out of the case, and made his bolt quite tight. He insisted that he had loaded under the book max with MAGPRO. This is why I prefer to use the Hodgdon online manual and try to stick to their EXTREME powders. While Alliant RL22 and RL 25 are great powders, for these applications, one has to be more careful when working up loads in cool conditions.