Author Topic: Barrel Twist (Read 8545 times)

TommyG · « **on:** August 19, 2017, 02:54:25 AM »

I was going to post this in gun building, but thought it might be more appropriate here. A few yrs back a co worker gave me one of those Kentucky rifle kits by CVA from around 1974. The kit is unfinished. No problem, I was just interested in the barrel figuring I could put it to some plain 2" maple I have left over from an earlier job, add a decent lock & triggers and maybe have a target piece for offhand shoots, plinking, etc.. The problem or question I have is this is a spanish barrel in percussion, 33.5" long, .45 cal., but the rifling looks to be 1 in 12, at least that's what I got when doing several checks with a marked tight fitting jag. Would this thing even work with PRB's with that fast rate of twist, or should I not bother and maybe just turn it into a 4th of July cannon. I have a pic of the rifling below.

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rich pierce · « **Reply #1 on:** August 19, 2017, 03:25:26 AM »

So how are you measuring it? I insert a tight fitting jag and patch combo and mark where the muzzle is on the ramrod. I take electricians tape, make a loop of it at the other end of the ramrod, and leave team tab ends stuck together pointing straight up. Pointing right down the middle of the top flat. I insert the ramrod further till the rod has made a full turn and the tape is once again pointing straight up. I make another mark on the ramrod at the muzzle. Take the ramrod out and measure between the 2 marks.

I've never seen 1 turn in 12" but I suppose it's possible. If so use it for pistol barrels with light charges.

TommyG · « **Reply #2 on:** August 19, 2017, 03:40:38 AM »

Rich, yes that's how I measured it as well, only with blue painters tape. I couldn't believe it myself and did it several times, each time coming close to 1 turn in 12". I have no idea why CVA would offer this kind of fast twist rate and was hoping that some of the guys we have here could maybe offer some insight. No big deal, just curious and the price was right.

Hungry Horse · « **Reply #3 on:** August 19, 2017, 03:48:19 AM »

If it's a 1in 12" twist it's not from the seventies, or it's no a CVA. Some of the early CVA Kentucky barrels were pretty good, but all I've ever seen were 1in48" twist.

Hungry Horse

WadePatton · « **Reply #4 on:** August 19, 2017, 04:20:12 AM »

1 in wHUT?!

Sounds extremely odd to me, but what do I know? I'm sure those who do know will come along and help sort this out. Nevermind me.

TommyG · « **Reply #5 on:** August 19, 2017, 04:28:11 AM »

Hungry Horse, I wish it were one of the 1-48 twist. Here's a pic from the box and of the barrel stamp. The guy left his invoice on there as well(along with an old fishing license), which of course I wouldn't post. All dated from around 1976. I would believe the twist rate if it were from say the late eighties, when the inline and sabot craze started to get traction, but I think 1-12 is even a bit fast for sabots as well. Maybe a factory mistake of some sort.

rich pierce · « **Reply #6 on:** August 19, 2017, 05:05:53 AM »

Rifling looks too deep for a bullet to work.

little joe · « **Reply #7 on:** August 19, 2017, 01:28:44 PM »

Rich In the photo is we are seeing from one end of the barrel to the other I,m not seeing near that fast of twist.

Standing Bear · « **Reply #8 on:** August 19, 2017, 02:27:46 PM »

In the op it says the barrel is 33.5" long. The pic of the illuminated bore shows approximately 1/2 turn in the length of the barrel. That would be a 1/66 twist.

Maybe the tight patch was slipping or the nag was unscrewing or?

TC

rhbrink · « **Reply #9 on:** August 19, 2017, 02:38:37 PM »

Agree with Standing Bear but I'm guessing about 3/4 of a full turn hard to say exactly but that would put it near to a 48" twist. If it was a 12" twist it have almost three full turns in 33.5 inches? Anyway good luck with your build!

RB

hudson · « **Reply #10 on:** August 19, 2017, 03:42:23 PM »

An early CVA kit I put to gather was 1 in 66.

Bob Roller · « **Reply #11 on:** August 19, 2017, 03:45:06 PM »

Quote from: TommyG on August 19, 2017, 02:54:25 AM

I was going to post this in gun building, but thought it might be more appropriate here. A few yrs back a co worker gave me one of those Kentucky rifle kits by CVA from around 1974. The kit is unfinished. No problem, I was just interested in the barrel figuring I could put it to some plain 2" maple I have left over from an earlier job, add a decent lock & triggers and maybe have a target piece for offhand shoots, plinking, etc.. The problem or question I have is this is a spanish barrel in percussion, 33.5" long, .45 cal., but the rifling looks to be 1 in 12, at least that's what I got when doing several checks with a marked tight fitting jag. Would this thing even work with PRB's with that fast rate of twist, or should I not bother and maybe just turn it into a 4th of July cannon. I have a pic of the rifling below.

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Obviously rifled on a machine set up for a cartridge gun. The early repro Colt Navy**
made for Navy Arms was rifled on a set up for a Beretta machine pistol. This barrel
you show might work with a short bullet like used in a 45-90 Winchester. I used to'
load my 1:18 Whitworth 451 with 40 grains of 3fg and a .445 patched ball so small boys
who were grandsons of a friend could shoot it without getting knocked off the chair with
a full load.

Bob Roller
** That info came from the late Val Forgett,owner of Navy Arms in 1963.

WadePatton · « **Reply #12 on:** August 20, 2017, 01:31:04 AM »

Looking at the bore pic this time, I must agree that the rifling does not appear to complete 2.79 revolutions in that length of bbl.

I don't see how the measurement can be correct without some optical illusion being at work in the pic.

Bob Roller · « **Reply #13 on:** August 20, 2017, 01:37:55 AM »

The whole thing looks like an hallucination to me.

Bob Roller

TommyG · « **Reply #14 on:** August 20, 2017, 01:50:22 AM »

Hey Guys, Thanks for all your input. The problem is the pic doesn't really capture the fast twist rate as the light shining in the end of the barrel sort of creates the illusion of a slower twist. I have several Rice barrels with 1-66 and a few Investarm Lymans with the 1-48. I can assure you when you hold this thing up to the light, it looks more like my .308. I just can't seem to capture that with my camera. I appreciate all your help, I was assuming it probably wouldn't be a good choice for a long gun but figured with all the knowledge and experience that we have here that maybe some of you guys ran into this over the years and could shed some light on how it shoots and maybe I would get lucky. No problem, like I said it was for free and I just started another build. I maybe will take Rich's advice and save it for a future pistol build as I never tried one and that would maybe be a good starter. Thanks Bob Roller for your insight as to what possibly could be going on here, with the fast twist it almost looks like it was rifled to be a cartridge gun.

Hungry Horse · « **Reply #15 on:** August 20, 2017, 01:58:03 AM »

Hey, a CVA Kentucky is basically a fence post posing as a gun anyway. If it is a 1 in 12" twist, cut it up into pistol barrels, and make firewood out of the rest. The brass buttplate is the only piece of furniture that might be salvageable, the rest is not a replica of anything.

Hungry Horse

WadePatton · « **Reply #16 on:** August 20, 2017, 04:15:05 AM »

Quote from: Hungry Horse on August 20, 2017, 01:58:03 AM

Hey, a CVA Kentucky is basically a fence post posing as a gun anyway. If it is a 1 in 12" twist, cut it up into pistol barrels, and make firewood out of the rest. The brass buttplate is the only piece of furniture that might be salvageable, the rest is not a replica of anything.

Hungry Horse

This. I agree. Make pistols and sell 'em. Faster twists "work" in pistols because lower velocities and also because most folks don't expect much accuracy from short arms.

D. Taylor Sapergia · « **Reply #17 on:** August 20, 2017, 04:55:59 AM »

This is not a 1:12" twist barrel! Look at the end of the barrel in the photo. Follow one land in its path toward the other end of the barrel. At best, it makes only one half a turn in the whole barrel length. So if the barrel is 33" long, the rate of twist is 1:66". Excellent photo, by the way...

WadePatton · « **Reply #18 on:** August 20, 2017, 05:39:50 AM »

Quote from: D. Taylor Sapergia on August 20, 2017, 04:55:59 AM

This is not a 1:12" twist barrel! Look at the end of the barrel in the photo. Follow one land in its path toward the other end of the barrel. At best, it makes only one half a turn in the whole barrel length. So if the barrel is 33" long, the rate of twist is 1:66". Excellent photo, by the way...

See reply #14 Taylor. Don't you remember the old pre-computers era (PCE) saying:

Don't believe anything you hear and only half of what you see?

Apparently this is one of those "seeing" issues we cannot believe.

Daryl · « **Reply #19 on:** August 20, 2017, 08:25:11 PM »

Quote from: D. Taylor Sapergia on August 20, 2017, 04:55:59 AM

This is not a 1:12" twist barrel! Look at the end of the barrel in the photo. Follow one land in its path toward the other end of the barrel. At best, it makes only one half a turn in the whole barrel length. So if the barrel is 33" long, the rate of twist is 1:66". Excellent photo, by the way...

Exactly!

The fastest rate of twist I have ever seen in a .45 calibre ctg. gun, was 15", with 18" to 22" being standard for many years. Elmer Keith once wrote that 24" would stabilize a 2,000fps 500gr. bullet just fine.

Joe S. · « **Reply #20 on:** August 20, 2017, 08:40:04 PM »

I still been looking at that picture and no matter how hard I try I don't see a 1-12 twist????with that photo you would see it IMHO

Bob Roller · « **Reply #21 on:** August 20, 2017, 09:59:53 PM »

Quote from: Daryl on August 20, 2017, 08:25:11 PM

Quote from: D. Taylor Sapergia on August 20, 2017, 04:55:59 AM
This is not a 1:12" twist barrel! Look at the end of the barrel in the photo. Follow one land in its path toward the other end of the barrel. At best, it makes only one half a turn in the whole barrel length. So if the barrel is 33" long, the rate of twist is 1:66". Excellent photo, by the way...

Exactly!

The fastest rate of twist I have ever seen in a .45 calibre ctg. gun, was 15", with 18" to 22" being standard for many years. Elmer Keith once wrote that 24" would stabilize a 2,000fps 500gr. bullet just fine.

The "trapdoor" Springfield used a 1:22 twist to stabilize a 500 grain bullet when in reality
was 525 grains.In trials at Sandy Hook NJ along a beach it beat the legendary 577-450 Martini-Henry
at all distances some of which were around or maybe more than 2000 yards.This old rifle
had no fancy rifling. What it had was 3 grooves and lands and on some specimens it was found
to have grove diameters of .465. The consensus was and probably a correct one was the 45-70 made better
use of the tightly compressed powder charge and the heavier bullet. The 577-450 if memory is right used
85 grains of powder and a 480 grain paper patched bullet. Potent but not as efficient as it should be.
I am no fan of the TD Springfield and after having a trapdoor break off in my hand while ejecting a fired case
I took it over to Bill Large's shop and made a muzzle loader out of it with a .450,1:18 with 8 lands and grooves.
John Marra,a local Home&Garden TV personality had one blow open when the thumb latch failed and allowed the locking cam
to roll over and unlock the action on firing.The abruptly ejected case hit the ejection pin and saved him for injury.

Bob Roller

TommyG · « **Reply #22 on:** August 21, 2017, 12:03:15 AM »

After all the replies and interest generated in this odd barrel, I just had to go back into the shop and try to take some better pictures. Now granted I'm no photo expert by any means. What I did was tape a piece of tracing paper over the end to try to get diffused light into the barrel to give the shot a bit more depth. I also fitted up the jag with a .022" bull denim patch, marked the rod and SLOWLY pushed in 1 full revolution, travel was just under 12". I didn't mean to create such a stir, apparently this is something really odd for whatever reason.

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Mike Brooks · « **Reply #23 on:** August 21, 2017, 01:59:25 PM »

I still only see 1/2 a turn.

rich pierce · « **Reply #24 on:** August 21, 2017, 03:10:29 PM »

Pretty sure the way the focus is, we can't even see the rifling at the far end enough to see it keep curling around. Anyway it is what it is, a curiosity.

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Author Topic: Barrel Twist (Read 8545 times)

rhbrink