Re: .300 WM vs. .338 WM
I am having very good success with the cutting edge bullets in those two calibers. Me and another guy on here are getting over 2900 fps with the 225 grain .64 bc out of our 338 winchesters. That bullet weight at that bc and velocity would probably give you your best long range results within the capability of the two cartridges. If I had to choose between the two that is what I would go with if it shot good out of your rifle. You said 1000 yards and that is the combo that would give you the best results on game to that distance. The 208 amax or 210 berger out of the 300 winchester is going to shoot nearly identical ballistically but the 338 cal 225 grain gives you better results on game. If you are going to do a lot of target shooting the 300 winchester would be better because those bullets are way cheaper. But accuracy is the key and I would keep the best shooter. I would also prefer to keep the remington for the action if you want to rebarrel one day.
Predictions are difficult, especially when they involve the future