Its only bad if you dont have the barrel length to use to its full potential...
If you only have a 24" tube, then yah its probly going to be a worthless POS.
If you stick a 26", better yet a 28", stick a 8 or 9" twist and shoot some heavy for caliber .257" bullets, your going to get some smoking velocities, performance in a .257" like you've never seen before, and you wont have "unburnt" powder promlems..
Personally, I think the 25-300 Win Mag is the better route to go. You have the option of using Lapua brass. There isn't chit for quality brass for the STW...Thats its only limiting factor..
Barrel life probly aint gonna be much more then 1000 rounds with the hotrods, but if you break the barrel in, and work up a good load, that takes what 75 rounds, practice a litle bit every year, say 100 rounds a year, that rifle will still last almost 10 years.
Still, 6.5" is better route to take. Ballistically they spank anything the .257" has to offer, afterall, since I like to shoot long range, thats what I"m looking for...As much as I love .257"'s, when my 25-06 barrel is toast, its getting rebarreled to a 6.5-06 AI w/26" tube, set up to shoot 140g AMAX or VLD"s...