Gain Twist vs. Straight Twist barrels

[P.Altland]

I recently picked up another Pietta revolver and want to get it accurized. Is there any benefit to the gain twist barrel? I know most of the guys doing accurizing are using straight twist barrels of 1:8 or 1:10. I have no intensions of using conicals. Round balls all the way. Anybody with thoughts or experiences?

[le piaf]

I have shot round bullets in pietta -30 years old , in pietta match, in uberti , in pietta with Lepage Pedersoli barrel (personnal mount), and now with an Hege maximum ,
There is no difference within gain twist and straight twist , accuracy come from good adjustment of the handgun , a correct loading and....... from the hand and the eyes of the shooter;) . I shot also with an original remington (group only in a playing card).
In my mind ,gain twist in handgun is only marketing for upper quality repros.

[Maillemaker]

Well, the theory behind gain twist rifling is that by starting the rate of twist off slowly the ball will engage the rifling properly before starting to have to start spinning, resulting in a a better conformance to the rifling. Whereas if it hits the rifling at full twist from the start it may strip on the rifling.

I've never shot anything with such rifling so I don't know if it makes a real difference or not.

Steve

[Jim Wimbish, 10395]

I have shot three guns that I know of with gain twist barrels: Burnside, Pietta Shooter's revolver, and a #1 Maynard in 36 caliber. There is probably not much if any advantage to gain twist for the light loads that we shoot. It might have some advantage for heavy loads. What the slower initial twist should do is make it easier for the bullet to get seated in the barrel. There could be a slight advantage with the bullet further down the barrel as the powder burns resulting in less fouling and gas cutting. In my Maynard, I have noticed very little fouling and leading which 'May' be related to the gain twist. I checked several threads on the Web and couldn't come up with any problems specific to gain twist other than bring more expensive to manufacture.

[Charlie Hahn]

I play with gain twists in Muskets, Sharps, and the revolvers I build. Regarding the revolvers, the Hege, and the Italian shooter's model as well as the originals all have a gain twist barrel. From some of my picky customer's reports I believe that an equal fitted revolver with a developed narrow margin load with all the special care taken will shoot reasonably equal. However, the gainers do have an interesting personality based on range testing. You can feed the gun various granulations of powder of the same charge weight with a smaller variation. Also the charge weight can also vary a couple grains upward with little down range variation. This has been tested in 4f, 3f, 2f, and 1.5f and various brand names. The projectile and loading sequence is specific to each shooter and will not be shared here due to competitive prowess.

I believe this happens due to the increased pressure as the projectile is spun up in bore, and helps to consume more of the charge down bore. The projectile gains spin rate, and ballistic fill gains pressure. The barrel I offer has twenty data points to date, and all of them work the same way, (I wish I could say the same from my musket and carbine). In the revolver, the gain twist appears to offer a forgiving load/bullet variance, which is opposite from the musket and carbine gainers I have worked with.

The final twist rate is similar to other straight twist rates mentioned in the string.

CW Hahn