As mentioned the ONLY issue with the .323 calibers is lack of really high BC long range bullets. I shoot an 8mm Rem Mag. Definitely an overlooked and under-appreciated caliber. I've shot everything from prairie dogs to truckloads of antelope, deer, and elk up to Shiras Moose with it and it has been an outstanding weapon. I am a reloader, so it is easy to realize the full potential out of the gun. I could see with the proper bullet introduction that it could see a resurgence among some of the serious hunters. A few of my friends that guide in Alaska use the 8 mag extensively as back up guns for sheep and bear hunters. .338 calibers are awesome as well. For a dedicated elk gun I wouldn't drop below the .32 caliber mark, however that is just my opinion. I would say you could still eek another 150-200 fps with some of the newer magnum powders, but so little research has been done because there is little interest in the cartridge as a whole
With a stock 24" Barrel @55 degrees 4800 elevation I get the following with my worked up reloads, and none of them show any signs of excessive pressure and are "accuracy" loads.
160 barnes ttsx 3,470 fps
180 barnes X 3175
180 nosler ballistic tip 3212
180 nosler e-tip 3198
200 grain accubond 3015
200 grain matchking 3030
196 grain hornady match 3112