[Fed168]

What's a low sensitivity primer? I just installed a reduced power spring kit, and it mentioned possible failures with low sensitivity primers.

[Ed]

I would guess one for semi auto millitary types with a tendancy to slamfire. They are less sensitive to prevent firing when the bolt slams.

[Dave R]

I don't think anyone sells primers marked "low sensitivity". Some primers are just harder than others. For example, small _rifle_ primers are harder than small _pistol_ primers. Some companies (CCI, not sure who else) make mil-spec primers, which are harder than the other two.

[Jim K]

Military primers tend to be harder than commercial primers. But primer hardness is not just a matter of sensitivity. A primer not only has to resist pressure generated by the priming compound itself but also pressure that comes back through the flash hole from the burning powder.

If it does not have enough hardness and thickness, it can blow out or be pierced; if too much hardness, it can fail to fire. That is why the reloader should be careful never to switch rifle and pistol primers or to use standard pistol primers in magnum loads.

Jim