Gain Twist in BP Revolvers

[Ephraim Kibbey]

I had read threads on several different forums that said all Italian reproductions had straight rifling except the expensive shooter 1858s.

According to six Early and Modern Firearms (EMF) catalogs I just got, at least some of their black powder reproduction revolvers had 1 turn in 36 inch gain twist rifling.

They also brag that their reproductions' parts will interchange with first generation original percussion and SAA Colts.

These catalogs cover the time when Armi San Marco (ASM) was supplying EMF with their reproduction percussion and SAA revolvers ('60s - '80s.)

 

[Erwan]

This is what I have seen in 50 years on italian copies:

- Whitney .36 Palmetto, stripes 6 1/4 turn right step in either 190mm 1:30
- Remington 1858 .44 Uberti 2006 standard, 6 stripes right, 1/2 turn in either 200mm 1:16
- Remington .44 Pietta 1858 1980 7 stripes right, 1/4 turn in either 180mm 1:30
- Paterson 1836 Pietta 2004, 11 stripes right, 1/4 turn in either 250mm 1:40
- Walker Uberti 1847 2005 7 left scratching, 1/2 turn in either 225mm 1:18
- Uberti Dragoon 1848 2000 7 left scratching, 1/4 turn in either 200mm 1:30
- Navy Uberti 1851 1985 1994 7 stripes right, 1/8 turn in either 190mm 1:60
- G & G 1851 Southern copy brass Pietta Coltman 1985 7 straight stripes 1/8 turn in either 190mm 1:60
- Army Uberti 1860 1994 7 scratches left is 1/8 200mm 1:60
- Police in 1862 Uberti 1999 6 stripes right in 140mm or 1/4 1:22
- Starr Pietta 2005, 7 1/4 200mm straight stripes is 1:30
- Lemat Pietta 2004, 7 1/4 200mm straight stripes is 1:30
- Spiller & Burr, 7 1/4 180mm straight stripes is 1:30

 

[Jim K]

In regard to the original percussion guns, AFAIK, only Colts had gain twist rifling. None of the others did.

I recall once pulling down a rather nice 1860 Army and looking through the barrel. I did a bit of a double take; evidently at some point the barrel had been chopped and someone had welded a piece of Remington barrel on to "restore" it!! At least it was .44 caliber.

Jim

 

[yugorpk]

None of the lock parts in an Italian 1848 baby dragoon exchange in my Colt 1848. Maybe if I replaced ALL of them.

 

[LonesomePigeon]

Ephraim, which models had the gain twist rifling? Were any of them Colt models?

 

[Ephraim Kibbey]

Has anyone tested an early ASM barrel?

My EMF catalogs only list the specs for a few models so I do not know if the gain twist 1:36 is for all their models or just for the ones listed.

The prices do not seem to be greater for the models with the listed specs.

 

[Ephraim Kibbey]

LonesomePigeon - The following models of Colt Navy 1851 had elaborate listings of specs:

PER104 - Brass Frame
PER104CH - Case Hardened Frame
PER104N - Nickel Plated Frame
PER104RB - Round Barrel (Dragoon Style Barrel)

Caliber - 36 - .380
Rifling Twist - Gain 1 turn in 36"
Lands and Grooves - 6

also listed were:

PER104/44 - Brass Frame 44 caliber
PER104RB/44 - Round Barrel 44 caliber

Rifling was not specified for any other models in the 6 catalogs that I currently have.

I am curious if these specs are true for all of the ASMs or just those models.

yugorpk - The Colt parts ability to interchange is listed several places in the catalogs but maybe its just hype.

 

[Crawdad1]

I had a Third Generation 1860 Army and I tried to replace the backstrap screws with Uberti screws and they wouldn't fit. The Uberti screws would turn in, same thread, but the head of the screw wouldn't fit through the hole in the Colt's backstrap.

Ephraim, I didn't own anything on your list that was that old. I had a Pietta 'Shooters' model back in the 80's that shot reasonably well but I don't know if that Remington had a different twist rate from the standard issued Pietta Remington. But I do know one thing, my Second Generation 'Shooter's' model 51 Navy would outshoot my Remington.

 

[rcflint]

The Uberti screws are metric, and very close to the Colt, and a tap for the Colt screw will clean yup the hole for the Colt screw. The Colt is a #8-36, and the Italian a M4X0.70. M4 dia is .157, #8 dia is .164. 0.70mm is 36.2 pitch in inches.

The head on an M4 Uberti screw is 5mm (.197), the Colt is .208-.210. So, I have used Colt screws in an Uberti by re-tapping the hole to #8-36, and turning the head down to .197.. The reverse would leave more clearance in a Colt gripframe around the screw head, and a loose fit on the threads.

Another way would be to open up the Uberti frame countersink to accept the Colt head.

So, my experience is the opposite of yours, the Uberti head would fit the Colt loosely, and the Colt head would not fit the Uberti counterbore. Now, this is true on a real Colt, and the 2nd gen Colt is the same as an Uberti, but the 3rd gen Colt was finished here in USA with American made screws, your misfit could be a result of that. I never tried the gripscrew match with my 3rd gen Colts.

 

[Crawdad1]

You're right rcflint, it was the 3rd Generation Colt's screwhead that wouldn't fit through the Uberti backstrap's countersunk hole. I got it backwards.

 

[LonesomePigeon]

Crawdad1 did you get you Colt 2nd Gen 1851 Navy Shooter's Model new? I saw one online with box and paperwork included and in the paperwork was a folded paper target. I couldn't see what was on the target. I'm wondering if it was a test target showing the groups or if it was just a free target? Do you know if the Colt Shooter's Model was specially made to be a match grade pistol?

 

[Jim K]

I am not sure how gain twist rifling can be described as "1 in" anything. The whole point is that it is not uniform. The theory was that a soft lead ball/bullet would strip if subjected to rifling twist as soon as it hit the barrel. Gain twist allowed it to move straight (or almost so) at first, then pick up a spin gradually.

Jim

 

[Crawdad1]

Crawdad1 did you get you Colt 2nd Gen 1851 Navy Shooter's Model new? I saw one online with box and paperwork included and in the paperwork was a folded paper target. I couldn't see what was on the target. I'm wondering if it was a test target showing the groups or if it was just a free target? Do you know if the Colt Shooter's Model was specially made to be a match grade pistol?

I'm not sure Lonesome, I bought it back in 1977 and it had a brass backstrap and trigger guard which was unusual as most of the 2nd Generation Colts had the silver backstrap and trigger guard. But I do remember it was frickin beautiful.

 

[LonesomePigeon]

"I am not sure how gain twist rifling can be described as "1 in" anything."

Me neither but there's got to be some way of expressing different rates of gain twist.

 

[RPRNY]

The Lothar-Walther made barrels on Euroarms Rogers &Spencers target models had a gain twist.

 

[Ephraim Kibbey]

I believe that the "Rifling Twist - Gain 1 turn in 36"" above corresponds to the following description of Dixie's Pietta Shooter's model where "Gain" above and "progressive" below are analogous and the "1 turn in 36"" above matches "1 in 30"" below:

"This Remington, with its progressive rifling, won the gold medals in the World Muzzleloading Championships in Toronto in 1987 and in Pforzheim (W. Germany) in 1989....Blued steel frame. .44 caliber, blued 8”, tapered octagon barrel with .008” deep rifling. 1 in 30” twist, 5 land and 5 grooves...."

http://www.dixiegunworks.com/product_info.php?cPath=22_92_187_189&products_id=4098

Are not Gain Twist rifling and Progressive rifling synonymous with the turn ratio describing only the final amount of spin imparted not the degree of gain or progression?