a few notes on the original post. neck sizing only will not increase case life as far as split necks are concerned. it will help to minimize case head seperations. the same applies to partial neck sizing. partial full length sizing will not help with split necks any more than neck sizing. partial full length sizing will slightly reduce the odds of a case separation, or at least cause it to happen a few shots later. partial full length sizing bottleneck cases WILL push the shoulder forward, causing tight headspace and difficulty closing the bolt a no no for any hunting rifle. annealing necks properly will all but eliminate split necks, but will not help in any way with case separations when correctly full length sizing, where part of the aim is to set the shoulder back to where headspace is zero to a 1 or 2 thou gap. the best way to deal with separations is a min fls die made for your chamber by such as whiddens. this will work brass to an absolute minimum while still giving good fit and mechanical reliability. another help sizing necks is to only size them enough to give correct tension with a bushing. also when you use an expander, if they are sized the necessary amount only, they will not be stretched any more than necessary. custom chambers using a saami min spec reamer will not allow cases to expand any more than necessary, reducing brass movement in stretching. put all this into a package with a good method of annealing and you will get the most case life possible. for dangerous game, use new brass. some skilled people can polish factory dies to correct dimension of both body and neck. bruce.