.357 mag twist ?

[joneb]

Where do I find info on twist rates for Colt, Smith and Ruger for the .357 magnum ?

 

[Jim Watson]

Here.

Colt - 14"
S&W - 18.75"
Ruger DA - 18.75"
Ruger SA - 16"

Now why Ruger bothers to make different barrels for DA and SA revolvers, I cannot say, but it goes back a good many years.

 

[joneb]

Thanks Jim, but why the big difference ? Does this help explain the Smolt ?

 

[Jim Watson]

The difference definitely explains the Smolt. I think the 18.75" S&W twist was chosen as the slowest that would stabilize a 158 gr RN so as to accumulate less BP fouling. A faster twist will give a better chance at accuracy with long slow HBWCs and is usual on heavy barrelled PPC guns. There have also been some trials that indicate the faster Colt twist will generate more centrifugal force and mushroom a hollowpoint more, too.

What I do not know is how far back the 14" Colt twist goes. Were .38 Long Colts rifled at a slower twist for less volume of grooves to hold BP fouling? Maybe a Colt expert will come along.