Can a reciever made to feed a WSM cartridge be rebarreled for a .308-based cartridge?
No, at least not easily. The cartridges are fatter than most and require a different bolt face.
The whole WSM fad was a solution in search of a problem.
The 300 WSM was an excellent idea, never understood by most shooters. And that was on Winchester for not marketing the cartridge correctly. It was developed as a wildcat cartridge by Rick Jamison who named it the 300 Jamison who he had the idea patented. He approached Winchester and tried to sell them the rights to the cartridge. Winchester declined, but copied the idea anyway. Jamison sued and won. As part of the settlement Winchester, or anyone else who made rifles for the cartridge had to pay Jamison a royalty on both rifles and ammo for a certain number of years. I don't think they have to pay the royalties any longer.
I think Winchester was required to produce the rifles, but they sold them at a premium, as well as the ammo to cover the money they had to pay Jamison. The royalty issue kept other manufacturers from making 300 WSM cartridges or rifles which really hurt sales. Remington and Ruger developed their own versions to avoid the royalty but neither were nearly as good as the 300 WSM.
All of that helped keep buyers away.
But the biggest problem is that Winchester never understood Jamisons concept. The cartridge design burns considerably less powder in a more efficient design than 300 WM, yet only comes up about 50 fps slower at the muzzle with 180 gr or lighter bullets. That translates into recoil closer to 30-06 with performance much closer to 300 WM. The cartridge was meant to be used in smaller, lighter more compact mountain rifles for guys that hunted in rugged terrain at long range who wanted 300 WM performance with reduced recoil.
But Winchester marketed the 300WSM as just another 300 magnum and didn't build rifles designed to work with the cartridge. Most shooters saw the WSM was 50 fps slower than 300 WM and never bothered. But the cartridge has loyal following among guys who are putting together lightweight custom mountain rigs. It is also proving to be more accurate than any other 30 caliber cartridge. Hornady uses a 300 WSM test barrel when testing all of their 30 caliber bullets for accuracy and the 300WSM has beaten all of the long distance shooting records once held by 300 WM.
Comparing 300 WSM to 325 WSM. There are simply no good 8mm bullets to choose from. You can load a 300 WSM with the exact same bullet weights and they leave the muzzle within 25-50 fps of each other. On paper the 325 looks slightly better at the muzzle. But the 30 caliber bullets have much better SD and BC which means that within 100 yards the 300 is moving faster and with the better SD will easily out penetrate the 325.
Honestly the 300 WSM and the 7mm WSM were the only 2 that ever made sense. And used correctly both are excellent cartridges. Unfortunately the 7mm version is dead as is the 325. The 300 and 270 will survive and the 300 has a loyal following.
