My brother has a 7mm STW, it is a tac-driving - bug-hole making - straight shooting rifle. His is an Ackley Improved version of the STW and it is a very flat shooting rifle.
My brother is as ainul as they come when it comes to barrel care for his rifle. Every 3 rds at the range and he stops and cleans the bore.
My brother's favorite load (and yes he is a high velocity nut) is 140 Nosler BT @ 3500 fps. He likes the fact that he is only 20" low at 600 yds with a 300 yd zero.
The point being, if the rifle is properly cared for it will go much longer than if the barrel is not cleaned regularly.
You have to determine if the seller is shinning you, or telling you the turth.
On other thing regarding remingtons, I know that synthetic stocks (not the injection molded tupperware stocks) are the rage here on this web site. But do not be afraid of a pillar bedded laminated stock that came with the M700 LSS rifles. Those stocks are very well known for thier stability. I took 000 steel wool to mine, turning the finish into a matte, droped a blued matte finished barreled action in it and it looks really nice.
Bottom line, if you are looking for an STW, I would avod going cheap, go find a skilled riflesmith, have the action blueprinted, for real, order a barrel of your liking, have it properly put together, and never look back saying I wish would have...
Good luck and let us know what you do in the end.