Why can't a kentucky pistol be loaded the same as a kentucky rifle?

Question

The pistol just looks like a cut down rifle with a grip, so why is 40 grains of fffg the max. pistol load, yet the rifle can handle over 80 grains?

Answer 1

The main reason is pressure. The ammount of pressure that the rifle can withstand is far greater than what the pistol can.

Answer 2

Pressure is not the problem.  The barrel of a Kentucky pistol is the same as one for a Kentucky rifle except for the length.  If you put the same powder charge in a pistol of the same caliber as you would use in a rifle, the bullet does not have enough distance to grip the lands and start spinning as it would in a longer barrel.  If it is not spinning properly as it leaves the muzzle it will not be stabilized and will travel in an erratic path.  Of course, there is the recoil to think about.  A pistol, being much lighter than a rifle, will not absorb as much of the free recoil.  This will result in an increased perceived recoil.

Yet another consideration, and probably the most important, is the length of the barrel in relationship to the burning rate of the powder.  A rifle, having a longer barrel will have longer for the powder charge to be completely consumed before the bullet exits the muzzle.  An 80 grain powder charge will not have time to be completely consumed within the length of the pistol barrel.  This incomplete burning will result in erratic muzzle velocities.  Erratic muzzle velocities results in erratic points of impact for the bullet. Another way of saying it is inaccurate as h**l.

Answer 3

I doubt there's a difference in pressure capacity between two identical pieces that differ only in grip and barrel length.

Just a guess, but it's possible that the pistol (with its shorter barrel) wouldn't be able to burn off all that powder before the bullet exited the muzzle. In other words, it would be wasted, not dangerous.

Of course, I'm just guessing, and it might be very dangerous, so don't try it until someone smarter and closer to you than me says otherwise :)