Loading for a Remington model seven in 243 Win...9 1/4 twist and about an 18” barrel- this gun is off the shelf from 1984, I think, and is really a shooter. Purchased for my wife when she was 12, and has now been passed around among her 3 boys, and her 4 nephews. Now it’s mine to shoot and hunt with. Never failed to recover a whitetail, but I’d like to stretch it out a bit. I’ll shoot deer to about 250 yds, and I’m set up to shoot steel to 500. Please help with appropriate bullet wts and powder suggestions- thanks.