gain twist

[ken]

Is there any advantage to gain twist rifling. ?? Thinking of a 50 . What does it go from and what does it end up?

[Daryl]

Dan's .50 has a gain twist. He's the man to beat at their plank shoots. Seems to work for him, all 18 pounds of it.

[Chunker119]

The short answer is no. An accurate barrel is one where the ball and patch come out of the muzzle intact. A gain twist barrel in a muzzleloader makes no since as it stripes the ball and patch twice. Once fast to slow, then again slow to fast. If gain twist had an advantage over straight twist, it would be the most prominent. Hope this help.

Best of Luck,
Colton Fleetwood

[WadePatton]

Bbl makers who "do" gain twist can dial it in to suit your desires.

If a bbl makers only shot gain twist and match winners only shot gain twist, then I'd be more interested.  They don't, or it's the best guarded secret in all of blackpowder. 

I prefer to let the bbl maker decide the rate of (constant) twist and all those fussy lil' details that are his business to know best.  Frees up just a tiny bit of my mind. 

[hammer]

Gain twist for bullets, not balls?

[Dan]

The short answer is no. An accurate barrel is one where the ball and patch come out of the muzzle intact. A gain twist barrel in a muzzleloader makes no since as it stripes the ball and patch twice. Once fast to slow, then again slow to fast. If gain twist had an advantage over straight twist, it would be the most prominent. Hope this help.

Best of Luck,
Colton Fleetwood

This fella would have disagreed with you  on that.  There's more to the theory of gain twist than slow and faster etc. Likely it is not widely used because most barrel makers prefer to keep things simple.  His name is Richard Hicks and before his passing he was one of the gunners a fella had to beat at Canal Fulton and such if inspired to take home a medal.  He built that gun, barrel and scope. .50 caliber with a twisted twist.

[Bob Roller]

Gain twists like the one used by Harry Pope for elongated bullets with grease grooves would use (example)
a barrel starting with a 1:16 and end with a 1:15 3/4. Not really noticeable to eye examination unless you are looking for it.
Bill Large had a gain twist that was far more radical but I don't remember the start or finish.It DID shoot and shot really well.
N.G.Whitmore of Mansfield ,Mass. and possibly Potsdam N.Y. made picket ball guns used something like a 1:48 and ended in a 1:30 and these guns were record setters and declared as unfair competition in some shoots.
Germany's 8.8CM (88MM) high velocity cannon had a gain twist but the projectile had bands around it that supplied rotation and was a feared weapon in WW2. A long bullet won't negotiate a sudden change in pitch without stripping and destroying accuracy whereas the round ball or the odd looking picket bullet will. The picket requires the utmost care in loading but Whitmore proved it worked and worked well.He made 12 groove barrels.

Bob Roller

[smokinbuck]

Colton,
with all due respect, gain twist rifling only makes one change not two. When properly cut and properly charged it can be a very accurate combination. Many of the older bench and slug gun shooters used it to great effect.
Mark

[alyce-james]

Colton; Sir, I had a gain twist Numrich Arms barrel (45 cal.) in the late 1970's. "One transition " only. If you came to the range the same day I was there with the gain twist rifle, best you had your big boy pants on, it would be a shooting day. Have a good day. AJ.

[Daryl]

Dan's .50 has a gain twist. He's the man to beat at their plank shoots. Seems to work for him, all 18 pounds of it.

The barrel, if I remember correctly is a McClellan - or McKellan. Sorry if I got name spelled incorrectly. He uses 4150 modern barrel steel for his barrels.

Modern BR shooters are now having their barrels ex-rayed on specialized equipment that shows rate of twist changes inside the blank. They are having the blanks cut so the twist is actually increasing in rate, at the muzzle as these barrels shoot better than those with constant twist or decreasing rate - the increase in twist looked for, is thousandths of an inch - it matters to them in the search for a 'screamer' barrel.

Any obturation of the ball in the breech of the ML (I believe there is some - miniscule, perhaps, but some), will negate any deformity (or suspected deformity) suffered by the patched ball as it is loaded in the faster section then  pushed down into the slower section, then ejected from slow to faster again when fired.

[hanshi]

I don't know much about gain twist rifling, but have had personal experience with the accuracy potential of GT barrels.  My first ML, ordered back in the mid 1960s, gave me the choice of uniform twist or gain twist; I chose gain twist.   That rifle, now retired, shoots as well as anything I ever tried and might possibly beat every other gun I own.  Just one example and anecdotal at that but it  surely says something about GT.   

[Chunker119]

Gentlemen,

Please think about what I am saying here. Yes, gain twist rifling goes from slow to fast. However, when loading a patched roundball, the ball and patch is cut or "striped" twice. First it is cut when loading, going from fast to slow, then it cut the second time as the rifle is fired, slow to fast.

I would also like to make it perfectly clear that this man asked if there is an advantage, and that I never said that there are no "gain twist" barrels in existence that aren't accurate. As I stated in my first post, ANY BARREL in which the ball and patch exit the barrel intact will be accurate!!!

[Longknife]

I can vouch for the accuracy of a gain twist round ball barrels. In the early '80's I picked up a pretty nice Ohio made, half stock percussion rifle from a local collector. Of course, the rifling was gone, so I sent the barrel off to Bob Hoyt to have it bored and re-rifled. Bob said he had only done  larger bored rifles in gain twist and mine would be the first 'small" bore (.40 cal). The "gain would be about "20" in the 36 inch barrel so we decided on starting at 60 which would put the muzzle end at 40. This rifle would shoot any loads from 20 grains up to 60 grains with extreme accuracy.  No, I didn't save any targets or record any data and I didn't have a regular twist barrel to compare it to but I (and every one else) was very impressed with its accuracy. I still have that little "40", maybe I need to get it out and wring her out again!!!!

[Standing Bear]

Long knife I'd be glad to pickup the neglected .40 and wrong it out" for you.  Say 10-15 years of wringing?
TC

[Daryl]

Gentlemen,

Please think about what I am saying here. Yes, gain twist rifling goes from slow to fast. However, when loading a patched roundball, the ball and patch is cut or "striped" twice. First it is cut when loading, going from fast to slow, then it cut the second time as the rifle is fired, slow to fast.

I would also like to make it perfectly clear that this man asked if there is an advantage, and that I never said that there are no "gain twist" barrels in existence that aren't accurate. As I stated in my first post, ANY BARREL in which the ball and patch exit the barrel intact will be accurate!!!

"Any obturation of the ball in the breech of the ML (I believe there is some - miniscule, perhaps, but some), will negate any deformity (or suspected deformity) suffered by the patched ball as it is loaded in the faster section then pushed down into the slower section, then ejected from slow to faster again when fired."

[Daryl]

I suspect the answer to Ken's question, it maybe to quite possibly- perhaps probably. It will depend on the rate and load, of course.

Now, the plank shoot is at 60yards - ask the shooters from Wyoming and Montana who compete in that event, what their powder charges as well as ball and patch combinations are. No thumb starting or "squib" loads.

[little joe]

Had a 50 cal.gain twist by Bill Large and it was an excellent shooter, best I ever had. Many people pass judgement on something they have never tryed. Try one and you will be suprised.

[Dphariss]

Is there any advantage to gain twist rifling. ?? Thinking of a 50 . What does it go from and what does it end up?

No advantage so long as the barrel has a uniform twist.
Some supposition here...
Gains vary all over the place. With long bullets a slight gain is the best idea. Perhaps 1/2" gain IE 11" to a 11 1/2" or maybe 10 at the most.
With short bearing surface balls or picket bullets then gains may be as much as 10-12 or more.  48" to a 36". It was thought, I suspect, with cloth patched bullets that this reduced initial twist reduced the tendency to "blow" the patch during initial acceleration.
Dan

[Dphariss]

OK Got that done so I will add a little.
Gain twists.
Its known that if the twist slows at the muzzle accuracy can really suffer. Some button rifled barrels have variations in the twist down the length of the bore.
I suspect that the arrival of the picket bullet may have illustrated some failing with the sometimes (by modern standards) crude rifling guides which may have some variations in the twist that might not cause problems with a ball but very well might with a picket. So a gain would eliminate the problem and give a faster ending twist for the bullet. Just some thoughts.
Dan

[Daryl]

That is the way I 'see' it Dan. With a slight gain, there is no slowing of the twist rate due to rifling guide "wear", which is likely to have happened, else gain twists would probably NOT have been developed.
The excessive wear (compared to the middle) would be exacerbated at the initial pull and push of the guide, getting the cutter moving from a stop - once started it moves more freely, wearing the 'guide' less.
Does this happen today - don't know - but, know Dan is the Man in plank shooting & he shoots a gain twist round ball gun.

[hanshi]

Chunker119, if the prb is "cut" or "stripped" during loading and firing it is not the result of the twist; it would most likely be the result of sharp edges in the rifling.  GT rifling has to be used to be appreciated.