Re: neck or full length resize?
According to the Hornady reloading manual, you should neck resize if you are going to be firing the shell in the same gun you originally fired it in. Their reasoning behind this is that the case has already been fire-formed to the chamber, and full length resizing is needless working of the brass, plus the fire-formed brass is already supposedly concentric to the barrel. Personally if I was loading for someone else and especially if they were using a different model of rifle, I would full length resize to avoid feeding issues.
