Re: Tricks for loading a belted case
There's several ways to resize belted cases as the replys show. Depending on how one tests the results, any one of them will work to some degree. I prefer to do what has resulted in the best accuracy all the time; not a 3, 5 or even a 10-shot group. But best accuracy for at least 25 shots. Due to the statistical odds, any reloading process will produce great accuracy for a few shots once in a while.
Back in the 1960's and 1970's when belted magnums were used in 1000-yard matches, both top civilian and military competitors tried various full-length, partial-neck and neck-only sizing techniques. And bullet seating depth relative to the leade was varied along with neck tension. Best accuracy happened with new cases. None of these resizing techniques produced accuracy as good as what new cases would do. 25 or more consecutive shots into less than 7 to 8 inches at 1000 yards was only attained with new cases for both 28 and 30 caliber belted magnums.
Some folks finally did some critical measurements on the resized cases and found that a ridge a few thousandths of an inch in front of the belt wasn't sized down with a full-length die. For some reason, any fired belted case that didn't get its body full-length sized back to original diameter right in front of the belt didn't shoot too good. Neck-only sizing these fired cases tended to produce better accuracy than conventional full-length sizing does when this ridge is present.
By cutting off a full-length sizing die's bottom half inch or so and cutting off the top about half an inch below the shoulder, you end up with a body only sizing die. Smoothing the top and bottom edges lets a fired belted case be sized all the way to the belt eliminating that tiny shoulder in front of the belt. Some folks use a standard full-length die first (with its neck lapped out so expander ball isn't used) to set the fired case shoulder back about .003-inch then size again with this body only die. You end up with a belted case with virtually new dimensions. I've reloaded some cases 10 times using this method. Best I've done is 30 consecutive shots from a Kreiger-barreled M70 .30-.338 Keele well inside 7 inches at 1000.
Since then, a couple of folks started making these special dies; Innovative ??? (company name escapes me) has a collet version that works well but it's expensive.
Best suggestion? Simple. Do what works best for your techniques and hardware.