Light magnums in a semi-auto ?

Discussion in 'Guns & Ammo' started by Bear, Apr 12, 2006.

  1. Bear

    Bear New Member

    Jan 2, 2005
    I know they say not to but surely someone has tried it. What were your results ? Why do the say not to use them ?
  2. glennasher1

    glennasher1 Well-Known Member

    Sep 16, 2004
    Radcliff, KY
    Light magnums are loaded with slower burning powders than regular ammo, and loaded with a LOT more of it. Semi-autos are generally set up to work with a medium-fast powder, to cycle the bolt at a particular speed. YOU CAN, AND WILL, damage a semi-auto by shooting light mag ammo in it, the bolt will cycle too fast, and come back too hard, for the internal parts to bear, at least for very long. That's why they say DON'T DO IT, right there on the box. Sure as shooting, some dummy will do it, and bend his rifle, and blame the ammomaker. It'll be his own fault.
    The old M1 Garand rifle, that my Dad carried in the Army, is a case in point. While the action is very strong, the operating rod, that works the bolt, isn't strong and is oddly shaped. It works fine with powders in a medium burning range, like IMR-4064, H-4895, W748, H-335 and others in that range. Load some ammo with H-4350 or IMR 4350, and you WILL bend that op rod, likely as not, on the first shot. The slower powders burn in a different pressure curve, and it plays hob with the hole in the barrel that bleeds off pressure to work the action. By that, I mean that the higher pressure is carried further down the barrel, and when it hits that port for operating the action, it just SLAMS it, and that isn't what it's designed to take.