I think the STW is simply one of the most under-utilized rounds in the industry. BUT its probably for good reason. The round is only marginally ahead of the 7RemMag (and then more on paper than the effects on game) and as was mentioned you have to go with magnum length actions and 26" pipes to realize the full effect of the caliber. Also as was stated, the factory STW ammo offerings are just plain embarrassing at best!
Stoke up the STW with handloads and you will begin to see it gain its stride. But the same can be said for either the 7Rem and the 300Win. They are completely capable with 24" barrels as well. I have never seen a STW do anything that a 300Win couldnt have done equally, and cheaper as well.
If a 7 super is wanted then I personally would step on up too either the 7Ultra (again limited ammo offerings over the counter!) or go flatout and go for the Lazzeroni Firebird (his ammo is HOT HOT HOT but you better take your loan officer's card with you when you buy ammo, assuming you can find it). The STW has been around for years, but I believe it was just standardized to late in the game, the various factory super mags overtook it before it caught on with ammo makers.
Also as was said, if you are like myself and plenty others and have a safe full of rifles and just want another "just for farts n giggles" then by all means don't let us stop you! The caliber is certainly more than capable when loaded correctly (but can't the same be said for most other calibers when you get right down too it?

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As for the 7WSM, its practically a failure in this country but is making headway on other continents! I simply haven't seen any reason NOT to like the WSMs,
RA