RE: 25 WSSM
I've only handled the .25WSSM once during an evaluation period a local gunshop likes to have done when new stuff comes out-they hang up flyers and stuff like that posting their results in the store, and they know how stuff performs when people ask about it...not to mention they really boost their customer satisfaction since they let "loyal customers" like myself do the test drive!!!
But I digress...It was a sweet rifle. Very accurate, most of my 100yrd groups could be covered with a quarter from a bipod using a 4-16x42mm glass, and the chrony data showed that it should be very efficient for deer.
On the barrel burning, I don't think this will be a problem at all...A lot of development went into these WSM and WSSM rounds, they're not really extreme pressures considering their extreme design. Because these aren't really Magnum versions of their parent cartridges, instead they are equivalent performers in a smaller package, they should not offer any increased bbl wear. The ONLY possible, yet very unlikely circumstance I could see would be increased throat erosion rate, but I highly doubt it.
From what I have heard, these rounds are no higher pressure than most of the 7mm mags available, which suggests that they wouldn't be any more problematic than those proliferent rifles.