Originally Posted by jwp475
Originally Posted by BufordBoone
Originally Posted by jwp475
Burford, in your experience how does twist in a defensive handgun round affect performance?

Typically, faster RPM results in earlier expansion.

Earlier expansion usually causes less penetration.

Twist rate plays a significant part in RPM.


So pretty much the same as in rifle rds. I wasn't sure the handgun had enough velocity to make a difference. I know that you I would know

Yes. Looking at it from the standpoint of a std. 165 gr. bullet at 1150 and a "mild" one at 1000:

Changing just the twist rate:
When fired at 1150fps in a 1:10 it has 82,800 RPM at exit
When fired at 1150 fps in a 1:16, it has 51,750 RPM at exit

Changing velocity and twist rate:
The same bullet fired at 1000fps in a 1:16 has 45,000 RPM at exit


FYI, I've never seen .40 S&W loads marked at being for any particular twist. I've also seen the same bullet loaded at 1150 and 1000.

What was that "Buyer Beware" phrase? "Caveat Emptor"