Reloading belted cases is not really any different than other cases. I usually fire every case once just to get it to chamber size and then load it up with my hunting laod.
I don't shoot benchrest so my principle concern is hunting accuracy. Belted cases have over the years been "magnum" cases and some variaton of H&H cases. In other words,if you were a long range hunter you were most likely using a belted case because you needed the velocity in order to deliver a killing impact at long range.
Probably the most famous of the long range benchrest clubs is at Willaimsport Pennsylvania. These people have been shooting 1000 yd matchs on some ole ridgeline with nasty winds for about half a century. You can look at the cartridges that are used and you will find many many 300Wby based wildcats.
Read the results and you can make up your own mind about belt or no belt.
In fact, if you read Howard Wolf's advertisement of smithing 50% of the winning guns, he says he specializes in the 30-378 Wby -- not only belted but double radiused too. Maybe he is an idiot and don't know anything about guns. [img]/ubbthreads/images/graemlins/confused.gif[/img]