Originally Posted by
Muley Hunter
A 1-70 twist barrel twist the ball one time in 70" of barrel. A 1-20 twist only needs 20" of barrel for one turn. Most pistols are only half of that. Let's say 10" of barrel. It only spins the ball 1/2 turn with a 1/20 twist. A 35" barrel will spin the ball 1/2 turn with a 1-70 twist.
So, they're both spinning the ball the same amount. The ball needs to spin to be stable. A 1/70 twist in a 10" barrel would not spin the ball enough to be stable.
Muley read this very slowly so you can comprehend. Regardless of twist rate a projectile will continue that rotation after it leaves the barrel. The barrel length has nothing to do with it. If that same 10" barrel had a 1:70 twist rate and you loaded it with say an 80 grain charge it would stabilize the ball the same as if it was fired out of a rifle. Lets make this so even you can understand. If you have two twist rates - a 1:60 and a 1:20 the projectile from the 1:20 will be rotating 3 times faster than the 1:60. At 10' from the muzzle the projectile from the 1:60 will have made 2 revolutions while the one from the 1:20 will have made 6. All the twist does is start the process. It doesn't matter if the barrel is 4" or 40".
Like I have surmised or assume. The faster twist in a pistol may only be necessary due to the lower velocity because of the lighter charge in order to stabilize the ball. That is the only logical explaination. Otherwise one could use a 1:20 twist in a rifle with an 80 grain or more charge and a PRB with good accuracy. But we all know that is not the case.