Author Topic: gain twist vs straight twist (Read 12437 times)

FRJ · « **on:** March 09, 2012, 08:34:52 PM »

I would like your opinions of gain twist rifling vs conventional rifling. Thank You, FRJ

James Wilson Everett · « **Reply #1 on:** March 09, 2012, 08:56:04 PM »

Gain twist barrels cannot be freshened.

Jim

Shreckmeister · « **Reply #2 on:** March 09, 2012, 09:27:49 PM »

I assume they Could be freshened on the rifling bench that cut the barrel originally?

Longknife · « **Reply #3 on:** March 09, 2012, 09:44:09 PM »

Back in about 1980 or 81 I had just finished reading Roberts book. I was convinced that I had to have a gain twist barrel to give me a little "edge" at the local shoots, I had Bob Hoyt rebore and rifle an original barrel off of an Ohio percussion rifle. It was bored to .40 cal. and had a 1-60 to 1-40 twist. He told me at the time he had only been doing larger bores in gain twist and mine would be the first "small" bore. I was amazed at the accuracy I could get out of this barrel. I used it at lot of local shoots and every fall would take my limit of bushy tails any time I went out. I do not have any saved targets and I did not have a regular twist barrel to compare it too but I was very impressed with its accuracy. The barrel was much longer at 37 inches and about 15/16 across the flats, which made it "hang" much better than my previous rifle. This extra weight and length could also contribute to its superior accuracy over my previous rifle. All in All I would say that a gain twist barrel is very accurate and as most barrels, and they shoot better than anyone can hold them. Are the better than a reg. twist?---that has been debated for over a 100years but I would not hesitate to have another one done.....Ed

(I still have the gun)

Bob Roller · « **Reply #4 on:** March 09, 2012, 10:07:27 PM »

This will NEVER be settled but it is fun to talk about. If you look at Major Roberts book,you will see a man by the name of Howard Irish who used a 40 caliber Whitmore to devastate turkey shoots in the Northeast. N,G,Whitmore made a 12 groove, gain twist barrel and even the elegant little target/offhand rifle he made for General Grant would hit the lid of a cap box at 110 yards with no effort. Walter Cline had a similar rifle in 43 caliber that put all of the shots on a quarter at 186 yards from a rest.
Harry Pope had a gain twist but the rate of acceleration was 1 in 16 to 1 in 15 and 3/4.
Brockway and others used a uniform twist as did others and no one complained about a lack of accuracy. I tried my best to get Bill Large to copy the Whitmore 12 groove idea but to no avail. I did help Bill make a gain twist guide for a rifling machine but do not remember the rates of twist and change it had.

Bob Roller

The other DWS · « **Reply #5 on:** March 09, 2012, 10:30:42 PM »

Right now, in the single shot (cartridge) competitions, the gain twists created by Canadian barrel maker Ron Smith seem to be winning an inordinate portion of the matches--some even use a slightly choked bore as well. Of course those are breechloaders with the lead slug in direct hard contact with the rifling. the theory seems to be that the changing twist and tightening bore keeps a constantly improving gas seal. but he also makes a really really good precise barrel anyway.

In a PRB rifle I'm assuming that the tight-fitting patch can shift and flex a bit better than a naked lead ball to accommodate the changing rifling pitch--going both ways and on the "power-stroke" it had the added impact of the burning gas pressure to give and "improved" grip and seal.

LRB · « **Reply #6 on:** March 09, 2012, 10:40:52 PM »

Were these not elongated paper/cloth patched bullets loaded through a false muzzle with a mechanical bullet starter, using a telescopic sight, and not a round ball rifle ? Impressive shooting none the less, but have little relation to an open sighted round ball gun.

Dphariss · « **Reply #7 on:** March 09, 2012, 10:46:15 PM »

Either will shoot extremely well if made right. It has nothing to do with sealing the bore.
My heavy match rifle, in the final production stages, has a gain twist McLemore barrel and seems to shoot very well but its still in testing it does not seem to like light charges as well as heavy. Twist is unknown.
The gain for RBs and Picket bullets can be considerable. However, bullets with long bearing surfaces gains over 1" can cause problems with the bullet having deformed, the rifling cuts in the bullet are much wider than the lands. Does not matter is "naked" or paper patched. Slight gains even 1/2" or as Bob stated 1/4" in bullet barrels have proven to be VERY accurate.
I have a friend who was involved with a company that was making gain twists at one time for bullets. And they had a formula for a slight gain that was the best shooting barrel they made consistently.
Now....
Why?
Reverse gains are very bad. Well proven, at least with bullets.
So a carefully made barrel made with a guide with a slight loss of twist at the muzzle is poison. Match shooters in the modern world have barrels checked for this and have them cut at a point where the twist is uniform or gaining. There ARE variations in the twist of most if not ALL "straight twist" barrels but it takes fairly sophisticated equipment to find them.
http://www.riflebarrels.com/articles/barrel_making/twist_machine.htm

To eliminate this, if they even knew about it back in the day, someone tries a gain (I have no idea when the gain twist came about, it could be very old) and it shoots far better than his faulty "straight twist" barrels do. Instant convert to the gain twist... If the barrels won matches consistently the demand grew. I suspect this was why it was pretty popular in the east with the picket shooters.
Anyway the gain twist was very popular with picket bullet guns and of course was used in RB rifles as well.

If my memory is correct Pope was asked how he lapped a gain twist barrel and he said "with brains"

Dan

cmac · « **Reply #8 on:** March 10, 2012, 12:41:13 AM »

I was told there isn't much improvement in accuracy within the 100 yd field but improved at longer ranges

Bernard · « **Reply #9 on:** March 10, 2012, 06:40:40 AM »

I have made a barrel for a rifle I am presently working on. I used brass for the material, bored and reamed it to .538 at the breach to .534 at the muzzle. A friend and I worked together to build a rifling device which allows us to run left, right, straight or gain twist rifling in a variety of numbers of groves. In my barrel we cut 12 grooves, left hand twist with a gain from 1:70 in a parabolic curve to 1:18. We cut buttress rifling .006 deep. We tested this barrel and found that it shoots very well and remarkably seems to hold elevation between 50 and 100 yards much better than other rifles I have but the tests were not done with the barrel mounted in a stock so no conclusions can yet be drawn. I am very pleased with the result so far.

Curt J · « **Reply #10 on:** March 10, 2012, 06:47:01 AM »

It was not just in the Northeast that gain twist was popular. There were many of the better makers in the Midwest who favored it too. Henry P. Brunker, in Ottawa, Illinois, was a noted maker of target rifles. Nearly all of the heavy target rifles he made were turned for a guide bullet starter and rifled with gain twist. Some had false muzzles. There are several accounts of his rifles being used in matches at "a quarter-of-a-mile". Thirty miles down the river Edward Kline, at Henry, Illinois, was advertising "eighty-rod guns, grooved with gaintwist, with patent muzzles and other attachments, made to order, from $28 to $40." Others who used gain twist included (but are not limited to), Wilson Duncan, in Quincy Illinois; J. J. Freitas. in Springfield, Illinois; Daniel S. Ebersol, in Ottawa; Merton S. Hendrick, in Aurora, Illinois; and Jasper A. Maltby in Galena, Illinois. If they did not find that it gave superior accuracy, they would not have been using it.

Dphariss · « **Reply #11 on:** March 10, 2012, 09:49:49 AM »

Quote from: Bernard on March 10, 2012, 06:40:40 AM

I have made a barrel for a rifle I am presently working on. I used brass for the material, bored and reamed it to .538 at the breach to .534 at the muzzle. A friend and I worked together to build a rifling device which allows us to run left, right, straight or gain twist rifling in a variety of numbers of groves. In my barrel we cut 12 grooves, left hand twist with a gain from 1:70 in a parabolic curve to 1:18. We cut buttress rifling .006 deep. We tested this barrel and found that it shoots very well and remarkably seems to hold elevation between 50 and 100 yards much better than other rifles I have but the tests were not done with the barrel mounted in a stock so no conclusions can yet be drawn. I am very pleased with the result so far.

This is interesting. 1:18" ? I would like to read more about this as testing progresses.
But you may find that the accuracy will degrade if the bullets are not carefully weighed. The faster twists require more perfect bullets.
Holding elevation is purely a matter of velocity and ballistic coefficient.

Dan

Dphariss · « **Reply #12 on:** March 10, 2012, 10:10:16 AM »

Quote from: Curt J on March 10, 2012, 06:47:01 AM

It was not just in the Northeast that gain twist was popular. There were many of the better makers in the Midwest who favored it too. Henry P. Brunker, in Ottawa, Illinois, was a noted maker of target rifles. Nearly all of the heavy target rifles he made were turned for a guide bullet starter and rifled with gain twist. Some had false muzzles. There are several accounts of his rifles being used in matches at "a quarter-of-a-mile". Thirty miles down the river Edward Kline, at Henry, Illinois, was advertising "eighty-rod guns, grooved with gaintwist, with patent muzzles and other attachments, made to order, from $28 to $40." Others who used gain twist included (but are not limited to), Wilson Duncan, in Quincy Illinois; J. J. Freitas. in Springfield, Illinois; Daniel S. Ebersol, in Ottawa; Merton S. Hendrick, in Aurora, Illinois; and Jasper A. Maltby in Galena, Illinois. If they did not find that it gave superior accuracy, they would not have been using it.

Yeah, the gain twist was likely everywhere, even California by the late 1840s. There were quite a few Schuetzen and multi-purpose target/hunting rifles being made all around the nation and the Picket was used for 200 yard Schuetzen and for the 80 rod matches. These rifles eventually evolved into the heavy slug gun that appeared by the Civil War and this were capable of fine accuracy to 200 rods+ but these often used a straight twist for reasons already mentioned.
I was thinking of where it likely originated in 19th century America and did not get it typed quite right. There were a number of very serious rifle clubs in NE America by the Civil War era and most of the really good picket and slug gun MLs came from people in this area or people who shot against them or studied their rifles.

Chapman in "The Improved American Rifle" talks of shooting small groups at 80 rods, if IIRC, or more with "buggy rifle" with a detachable stock shooting a picket bullet.

I have wondered about the why and can only think that the positive gain in rotation to the muzzle was the key as per the previous post. It is very important and the gain twist would eliminate any possibility of the twist gong sour at the muzzle.
But short of finding some detailed description this is trying to get inside people's heads and this is just impossible.
Maybe I need to read Chapman again, its been awhile.
Bedtime
Dan

bgf · « **Reply #13 on:** March 10, 2012, 10:30:38 PM »

Its probably all wrong, but I think the advantage of the gain twist has to do with allowing a higher final spin rate but without the patch stripping or bullet deformation of the faster twist at the breech, i.e., once it is spinning slowly, it is easier to get it spinning more quickly. So, it could allow heavier charges than a "fast twist" barrel, but not require them as a slow twist barrel does, perhaps. Just a guess.

Daryl · « **Reply #14 on:** March 11, 2012, 04:57:33 AM »

Modern ctg. BR shooters who are quite serious, have or used to have their barrel blanks 'diagramed' and printed out in cross section as to their twist exactly. This would allow them to cut from each end, to place the BEST 20" or whatever length they were making it, from the section with the most exacting twist, with the gain at the muzzle. With such a barrel, the shooter shot more 'screamer' groups than one who bought a BER quality barrel cut to length and just mounted it.

What can be drawn from this? Merely that having a slight gain at the muzzle, is productive to the accuracy potential of the rifle, all else being equal.

What does this mean to our iron sighted round ball rifles? Less than with a ctg. gun with scope, but the potential for improved accuracy is still there. It will take a good competitor and experimentor to find and utilize that potential, but that's what makes a consistant winner in any game. The one who doesn't care or doesn't think anything matters, as I'm only shooting offhand anyway, also shoots in the match.

FRJ · « **Reply #15 on:** March 11, 2012, 05:19:56 AM »

When I originally wrote this post it was in the building section as I was considering using one on an upcoming build. Now I find myself needing to have a barrel re rifled and am thinking of having it gain rifled. It is a hunting rifle only. So here's the new question. The rifle I just bought is a beauty of a 45 caliber 42" long barrel, flintlock. It has been sitting in a safe for 35years and while the rifling is beautiful there are rust blemishes inside the barrel caused by surface rusting from sitting in the safe unprotected. It shoots great but I cant stand the sight of these blemishes so I'm thinking of having it re bored and rerifled. I'm thinking of the gain twist as long as I'm going to rifle it anyhow. So I'm thinking of taking it from 45cal to 50 with gain twist. What do you all think? FRJ

hanshi · « **Reply #16 on:** March 11, 2012, 06:04:57 AM »

I have an H&A .45 underhammer I ordered (45 years ago) with a gain twist bore. Though the hammer & tg/spring are worn out now, that barrel would stack ball like you wouldn't believe. Can't say for sure it was the gain twist but..........

Dphariss · « **Reply #17 on:** March 11, 2012, 06:54:55 AM »

Quote from: FRJ on March 11, 2012, 05:19:56 AM

When I originally wrote this post it was in the building section as I was considering using one on an upcoming build. Now I find myself needing to have a barrel re rifled and am thinking of having it gain rifled. It is a hunting rifle only. So here's the new question. The rifle I just bought is a beauty of a 45 caliber 42" long barrel, flintlock. It has been sitting in a safe for 35years and while the rifling is beautiful there are rust blemishes inside the barrel caused by surface rusting from sitting in the safe unprotected. It shoots great but I cant stand the sight of these blemishes so I'm thinking of having it re bored and rerifled. I'm thinking of the gain twist as long as I'm going to rifle it anyhow. So I'm thinking of taking it from 45cal to 50 with gain twist. What do you all think? FRJ

Have it freshed if you can find someone to do it. This was the answer back in the day.
No need to bore and rerifle.

Dan

Daryl · « **Reply #18 on:** March 11, 2012, 06:26:24 PM »

Or simply lapp it yourself - easy enough and the cheapest solution and will do nothing but improve it. If you want, you can lapp in a taper or choke as well - been there. I merely followed NEd's book and directions - TMCLRifle- that one.

Dphariss · « **Reply #19 on:** March 11, 2012, 08:14:10 PM »

Quote from: Daryl on March 11, 2012, 06:26:24 PM

Or simply lapp it yourself - easy enough and the cheapest solution and will do nothing but improve it. If you want, you can lapp in a taper or choke as well - been there. I merely followed NEd's book and directions - TMCLRifle- that one.

Yes if it is still shootable wth good accuracy lapping is probably the best answer.

Dan

Standing Bear · « **Reply #20 on:** March 12, 2012, 02:59:13 PM »

Quote from: bgf on March 10, 2012, 10:30:38 PM

Its probably all wrong, but I think the advantage of the gain twist has to do with allowing a higher final spin rate but without the patch stripping or bullet deformation of the faster twist at the breech, i.e., once it is spinning slowly, it is easier to get it spinning more quickly. So, it could allow heavier charges than a "fast twist" barrel, but not require them as a slow twist barrel does, perhaps. Just a guess.

That is my understanding.
TC

Bob Roller · « **Reply #21 on:** March 12, 2012, 03:53:53 PM »

One thing is sure.The 12 groove gain twist used by N.G.Whitmore sure worked and worked well.I am surprised that no one has picked up on this idea.
To go to the absurd,has anyone here ever looked thru the barrel of a fine Colt 1860 Army revolver?. It has some sort of weird twist that looks iike it reverses directions.

Bob Roller

Dphariss · « **Reply #22 on:** March 12, 2012, 04:01:20 PM »

Yeah the Colt's percussion revolvers, the later ones at least, used a Gain. I had forgotten until Bob mentioned it.
It was the "in" thing at the time.

Dan

smokinbuck · « **Reply #23 on:** March 12, 2012, 05:39:46 PM »

I have a chunk gun that was built by Ron Borron using a Goodien barrel with gain twist. According to Ron it goes from 1-72 to 1-56. This barrel is 48" long in .45 caliber. I haven't shot it but Ron won a number of major matches and says it is a "super shooter".
Mark

Paul Griffith · « **Reply #24 on:** March 13, 2012, 03:22:25 PM »

I've been toying with the idea of cutting a gain twist barrel. My own take on it is that quite often the exit twist is on the fast side for the caliber. For instance the Borron gun ended at 56 in a .45. While 56 isn't too radical I personally like .45 in the 60 to 72 in a uniform twist barrel. So why not make the gain go from 100 to 72 or even straight to 72. And I'm still not sure gain relates to the shooting of roundballs in any way shape or form. The golden days of gain twist appear to be during the shooting of elongated lead bullets in the second half of the 1800s. With an elongated bullet, the bullet would be tight in the bore from start to finish because of the ever changing pitch in rifling. This may have been the functional reason it was popular. As soon as copper was wrapped around the lead bullet it would maintain its fit in uniform twist rifling & gain faded in popularity.

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Author Topic: gain twist vs straight twist (Read 12437 times)

FRJ

The other DWS

Bernard

Daryl

FRJ

Daryl

Paul Griffith