Q: I’ve been reloading ammunition for my .270 Winchester for many years and case life has generally been good. It has been my practice, after I get 10 reloads from my cases, to junk them and buy a new lot.
But a recent batch of brass I bought developed cracks in the necks and on the shoulders after only two or three reloads. Why does this happen? Is there any way of extending the life of brass?
William Higgins
A: Brass life is a subject near and dear to every reloader’s heart. There isn’t any way to quantify it but there are a couple of limiting factors: how hot our loads are and how much we work the brass.
We don’t notice it, but brass grows and shrinks in length after every loading cycle.
When it is fired, it expands to fill the chamber and gets a little shorter, and when it is re-sized it grows longer.
The amount of change is dependent on the size of the chamber in relation to the cartridge diameter and the dimensions of the sizing die. Thus, with every loading the brass work-hardens and becomes brittle.
The end result is the same — first, little cracks appear at the neck which later may extend down the shoulder.
While there is no fundamental difference in the ultimate strength of modern rimless and belted cases, there is a difference in the hardness of brass and the way it has been annealed.
The handloader is likely to encounter a batch of brass that grows faster than others and another which needs trimming as often as after every other firing.
Brass varies in hardness and, as you recently discovered, one lot may withstand many more firings than another, even if they are of the same make.
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