im building a long rang hunting rifle and im not sure of the caliber that I should go with I do know I want it to be a 7mm,30,or 338 caliber but not sure which one to go with. the gun will be sender weight or a little bit heavier and 28-29 in barrel. I don't think I well ever hunt any thing bigger than a elk, it will be used for white tales more than any thing.
7mm STW or 300wm will get you to 800yds with ease on anything up through Elk size game. IF you can put the shots where they need to be you can take that on out to 1,000.
300 Rum will take that on out to 1200 or so.
The 338wm again out to 800yds will definitely handle Elk with ease.
The bigger 338's give you a massively higher amount of energy which will carry you far beyond the others in range, and your shot placement is not as critical because at any range it delivers far more energy to the target.
Ouf of all of the above the 7mm STW is the real gem to shoot followed by the 300wm. In a 10lbs rig with a decent muzzle brake you can spit the 180-190 class bullets out at max velocity with extremely tolerable recoil. Even in my 8lbs rig the recoil is no problem at all.
The 300wm is about the same, but you can push heavier bullets at nearly similar velocities.
The 300 Rum in a Sendero weight rig or heavier will launch the 180's at warp nine and with a decent brake is a real joy to shoot. Even the 210's are no problem at all.
The big 338's bring with them a much greater recoil force and so in smilar rigs as for weight and muzzle breaks you are going to have much more recoil force to put up with. The good news is, it's more like a really hard shove than getting hit with a fast moving hammer and if you drive it right again, they are tolerable but you have to get a heavy rig to make them a pleasure to shoot.
That being said I have 3 STW's, 2 300wm's and one 300 Rum just to always ensure I have the right rig for any job... .