Apologies to Daryl
Had not read all threads and tried to be a smart donkey.
Of course straight walled, rimless, high pressure rifle cases need a belt.
I have never owned a 10.75X57 but I cannot think of a bottleneck case that needs a belt.
I do not like belts. They take up room and are not as smooth to feed. The new .400H&H and especially the .465 H&H have pretty sloped shoulders maybe that's why a belt was used?