bwaites Wrote:I like both cartridges, and I like the fact that the Norma will go into shorter actions. One of my concerns with that is that simply shoving it into an action designed for a smaller and lighter cartridge might not be really safe.
I suspect that even the actions typically used by the longer Lapua are borderline safe, simply because there isn't enough metal around the cartridge. I'm no metallurgist or engineer, but it seems to me that more steel is better when you start talking about the case diameters of these cartridges.
Maybe LRRPF can chime in on hoop stresses of a 1-1.25 inch diameter action stressed by these cartridges?
It's a pretty simple calculation.
σ(hoop) = p d / 2 t
where
σ(hoop) = hoop stress (MPa, psi)
p = internal pressure in the tube or cylinder (MPa, psi)
d = internal diameter of tube or cylinder (mm, in)
t = tube or cylinder wall thickness (mm, in) (outer diameter minus inner diameter)
Ideally you want sigma to be less than half of the yield stress of the material used.
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