I always wondered about .318s in a .323 bore. A while back I got a good deal on some Woodleigh 200 gr RNSN .318s and some 196 RNSN .323 so I decided to test it.

Since I didn't have a lot of bullets, I took some shortcuts. I used new brass, went straight to near-max loads with IMR 4350 (about 2,500 fps), and only shot 5 shot groups. I sandbagged the rifles on the bench, and fired a shot every couple minutes to let the barrels cool a bit. Test guns were a K98k with iron sights, and a Remington 700 Classic (old Weaver T6 scope).

The K98k averaged about 2" with either bullet at 100 yards, the groups overlapped about 60%. The Remington 700 gave me separate groups, around 1" for the .323s and around 1.125" for the .318s.

I'd hunt with either of them in my 8x57.