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Auto load velocity ?

Does the energy required to operate the mechanism of an auto loading arms subtracted from the energy available for propelling the bullet, thus giving lower velocity

Comments

  • FrancFFrancF Member, Moderator Posts: 35,278 ******
    edited November -1
    Yes that's why some subsonic loads will not cycle in rimfires. However in center fires, Going to low might cycle the action but may also reduce enough ummph to push the bullet out the barrel. Better known as a squib load. Enough to make the action work but, not enough to push the bullet through the tube.
  • walliewallie Member Posts: 12,171
    edited November -1
  • FrancFFrancF Member, Moderator Posts: 35,278 ******
    edited November -1
    Thanks Wallie for proving the point.[^]
  • Rocky RaabRocky Raab Member Posts: 10,886 ✭✭✭✭
    edited November -1
    That piece of copy proves nothing whatever. A total spread of 13 fps is so vanishingly insignificant that it represents no difference whatever.

    The concept is simply wrong. No self-loading gun even begins to operate while the bullet is still in the bore - therefore no energy is subtracted from the bullet. Once the bullet is gone, no energy can be subtracted. No velocity is lost regardless of action type.

    Total recoil energy is fixed and equal to the energy imparted to the bullet (See the works of a guy named Newton for proof.) Therefore, the only change is related to the weight of the gun; heavier guns have less recoil velocity, that's all.
    I may be a bit crazy - but I didn't drive myself.
  • sandwarriorsandwarrior Member Posts: 5,599
    edited November -1
    To the original question:

    To a VERY limited extent the operation of the autoloading weapon is affected by the energy it takes to cycle it. That IS why you get slightly lower velocities from SOME autoloaders.

    First you must consider the different types of autoloaders. The blowback type action is going to lose velocity faster than the limited hold placed on the fired case from say a .45 Auto. Then you have delayed roller blowback that holds even longer. Longer still is the gas operated AR-15/M16 in which the gas must travel down the barrel and back through the gas tube to the bolt carrier before the bolt unlocks and then cycles. Of course some of the air in front of the bullet helps "pre-load" the system. Then finally there's the gatling gun which holds the case firmly though the firing cycle. You don't lose any velocity with those over a manually actuated gun.

    As to the second part of your statement that is an entirely different matter. However, since it was brought up I will answer it simply. If a gun recoils during the course of the firing of the bullet, as a light gun in hand is wont to do, {edit} that energy will affect the bullets aim and velocity. Energy is transferred instantly through a solid object. Therefore if the gun moves backward it will affect velocity. But, if you take that same gun and hold it completely firm it will produce the same velocity it always would have. Again though, that has nothing to do with the auto-loading mechanism.

    (Sorry, I typed this on my wife's laptop this weekend and since I don't have the fine touch with it yet, it accidentally rearranged sentences.)
  • Rocky RaabRocky Raab Member Posts: 10,886 ✭✭✭✭
    edited November -1
    Even in a blowback gun, the brass case is held tightly to the chamber wall throughout the firing cycle, and only relaxes that grip when gas pressure falls AFTER the bullet leaves the muzzle. You may think it all happens instantly, but even common slow-motion photography shows otherwise.
    I may be a bit crazy - but I didn't drive myself.
  • Hawk CarseHawk Carse Member Posts: 4,296 ✭✭✭
    edited November -1
    There was a gunzine writer who actually did the shooting and got a result contrary to the common sense theory that the energy to function an autoloader has to come from SOMEWHERE.

    He chronographed .22 lr from a Ruger Mk II in normal operation and with the bolt clamped shut. Velocity was higher with the gun in normal operation than it was with the bolt locked shut. It wasn't MUCH higher but it was reproduceable. He did some theorizing about better gas seal as the case started to slip back in blowback but nothing provable in ordinary shooting.
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