ColJ wrote:Khan: would turning em down get me back to a short case life?
I don't know how familiar you are with it but if you want a good read on neck-turning check out here: Neck Turning Basics. Short version as it relates to what you're trying to do and what I was thinking though is this:
Neck turning isn't intended as prep work for necking down cartridges but a side benefit could be helpful in what you're trying to do.
As you know brass isn't perfect, it's made to certain tolerances and a margin of error. For the most part necks are excessively thick and/or uneven.
Neck turning is about removing the excess material and uniforming the necks. Uniform necks means consistent neck tension which means more consistent/accurate loads.
In your case of necking down cases, obviously when you are trying to turn a big neck into a smaller neck you're compressing the brass. If there is too much brass to compress into the space of the desired neck size something else has to give e.g. the shoulders crumple instead.
If you turned the necks first you'd be removing excess brass. Less to brass to compress = more success, less crumbled shoulders.
Have a look about 3/4 down the page of the link above, that'll give you an idea of how much you might be removing.
How turning the necks effects your case life comes down to your rifle chamber. If the chamber is cut tight and there is little room for the neck to expand when fired brass life will be good.
If the chamber is cut a bit more generously and there is more room for the neck to expand that may shorten the life. That's the case for all brass really though.
Get what I'm thinking?
