'60 and progressive rifling??

[Pulp]

I recall reading somewhere that the original '60's were made with progressive rifling, like the .460S&W revolvers are now.

First off, is it true?
Second, would it make that much difference in accuracy?

[Noz]

Yes.

No. Progressive rifling is effective only in barrels of length.

[hellgate]

The only original 1860 Colt Army I got to look down the barrel (from the breach) had progressive rifling. Don't know about effect on accuracy.

[Flint]

I don't know that accuracy was the intent of the progressive gain twist, it may have been to reduce leading or bullet stripping in the rifling, as the bullets were pure soft lead and are suddenly asked to start spinning.  Non progressive bores don't seem to have a problem, but with the beginning of use of conical bullets, it may have been tried as a theoretical problem.

I've never read any reason in Colt histories.  The Target Shooter Remington by Pietta has progressive rifling.

[Mako]

I don't know that accuracy was the intent of the progressive gain twist, it may have been to reduce leading or bullet stripping in the rifling, as the bullets were pure soft lead and are suddenly asked to start spinning.  Non progressive bores don't seem to have a problem, but with the beginning of use of conical bullets, it may have been tried as a theoretical problem.

I've never read any reason in Colt histories.  The Target Shooter Remington by Pietta has progressive rifling.

+1

[Arizona Trooper]

Usually progressive rifling means shallower grooves towards the muzzle. Springfield muskets had 0.015" deep grooves at the breech and 0.005" depth at the muzzle. Most CW pistols have gain twist, which is slow twist at the breech (such as 1 in 60) which increases towards the muzzle (such as 1 in 20). Burnsides carbines also have gain twist. I haven't looked down the barrel of every CW pistol, but of those I have, Colt Navy, Army and '49 pocket models are gain twist, as well as Remington Armys and Navys, Starrs, Coopers and Manhattans. If you are looking at an original that doesn't have gain twist rifling, be very, very suspicious.

[Fox Creek Kid]

"Gain twist" is the more common term. Colt & Remington both used used it in percussion revolvers & conversions as well but Colt changed to a straight twist on the SAA as tests proved there was NO BENEFIT to gain twist rifling. If there were, every benchrest barrel maker in American would be cranking them out. As it stands, there is one rifle barrel maker in Canada who makes gain twist barrels and rumors of someone else in the USA as of recent.

[madcratebuilder]

The high dollar Pietta 'shooters' model has 'progressive rifling'  One of it's main selling points.  Mine is a tack driver, but it may not be from the progressive rifling.  It has other improvements, like chambers matched to the bore.

[Driftwood Johnson]

Howdy

I agree with Fox Creek Kid. There was no proven benefit to gain twist rifling, so it was simply discontinued.