Multi-Round Revolver Pattern

In my last essay, I discuss how stuffing shortened wadcutter bullets into long revolver cases can increase the firepower of wheelguns.  It must have generated some interest, as a question was asked ….

What did the groups look like?”

If my faulty long term memory serves, the first round looked something like this.

bullseye target with pattern from a revolver multiround

(Please click on the picture for a larger version.)

The target was two feet across, and set 35 feet or so from the firing line.  The center hole was made by the projectile with the traditional bullet shape, and the other four by the light wadcutters.  I didn’t actually hit the exact center of the target, of course, or even the ten ring.  But I figured you would forgive me a little poetic license in the interest of clarity.

I can’t say what the pattern looked like for any of the subsequent 49 rounds, as I was just firing at the paper to get rid of them.  There were more holes than paper hanging downrange by the time I was done, so at least we know that ammo like this does a bang up job of tearing apart targets!

One would think that the lighter bullets would tend to rise above the point of aim, not fall below.  So why did things turn out this way?  Dunno.  Maybe it has something to do with the turbulence caused by the projectile out in front.

6 Responses to “Multi-Round Revolver Pattern”

  1. bull says:

    the bullets leave the barrel at the same speed but because E=1/2mv^2 the smaller bullets had less kinetic energy and higher drag they would loose energy faster.

  2. James Nelson says:

    Heavier bullets print higher than lighter ones because of recoil and velocity. The longer the bullet is in the barrel after firing, the higher the barrel will be elevated when it comes out. This phenomena is observable at even short distances.

  3. guy says:

    What James said. Thse longer the bullet stays in the barrel, the more time recoil forces have to act on both barrel and bullet.

  4. Sam L. says:

    It would therefore seem to me that the lighter rounds would come out while the muzzle is still rising, and print high.

    • Paul says:

      Once the bullet leaves the muzzle, it continues in its current direction, affected only by drag, wind, and gravity. The longer bullets (for a given powder charge) accelerate in the barrel more slowly, and therefore leave at a more upward trajectory, and print higher on the target. The barrel moves upward quite a bit, but the lightweight bullets just get out sooner. For an excellent treatment of this phenomenon, see Julian Hatcher’s Textbook of Pistols and Revolvers.

  5. James Nelson says:

    Sam, if a bullet didn’t achieve enough velocity to leave the barrel until after the end of the recoil pulse, it probably didn’t get out of the barrel at all.

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