Hi Trent, don't worry about the bullet jump or magazine space in the M700 .308. Just be sure to seat your bullets deep enough into the case so as to maintain bullet concentrity to the bore. Your magazine is 2.83" long but if you need to seat to 2.73" for a good neck grip and concentricity- do so, otherise accuracy will suffer.
The Amax is much softer than the SMK, they are worlds apart in performance and in their secondary role in long range hunting, the SMK's are best utilized in either the magnums or when you are up against animals weighing 200lb plus. Bear in mind, when the .308 gives a slow kill at 450 plus yards- its a slow kill. Often you don't even get any indication of a hit when using a stouter bullet at long range. You could perhaps add the VLD to your list of options if it available and priced right. The VLD and Amax give similar wounding. Good luck.
P.S, the 165gr Nosler BT is just as stout as the 165-180gr GK's. Wounding/speed of killing is the same from my research/autopsies. These have to be a little tough as the majority will be loaded in either the .30-06 or .300 mags.
Cheers, Nathan.