There are no free lunches so to speak.
The 7mm STW will go through BBL's depending on how much you shoot it, your loading practices, and how hot your barrel gets.
I rebarrel end mine at 1500 rounds, she still shot good groups but the velocity slowed as the throat eroded.
For many years I loaded 140gr Partitions and accubonds with a max load of IMR7828 for a muzzle velocity of 3625 fps. Layne Simpsons medium load for about 1989. ( Always use current load data)
My load was accurate and put the thumps on Elk way out there and is it was hell on sod dogs.
To increase my BBL life I would use a slow powder and heavier Bullets.
Mind you I will not shoot big game past let's say 600 yards, ( Wolves are the exception) my load is capable of much further but my self imposed limit of 600 yards insures for me Fair Chase.
Barrels on the STW may last several thousand rounds if one used the heaviest practical bullet for the job at hand as heavy Bullets require less powder possibly lower throat temps, your mileage will vary of course.
Love the STW been shooting it since 1994, yep I call mine "Old Meat in the Pot".