.338 bullets are no problem you can find them everywhere. If that is what you want go for it buy some 06 brass neck it up and have fun.

I have a freind that bought a remington 760 chambered in .358 win and could not find ammo. I necked up some .308 brass and he still hunts with that gun.

If that's what you want do it and of course bring it to a shoot.