Progressive rifling in a .45

[drago]

Has anyone had any experience with this caliber. I've heard in 50 and above it works well to flatten the trajectory. Round ball only.

[T*O*F]

Trajectory has nothing to do with rifling.  It is a function of projectile speed vs gravity.

[EC121]

Gain twist has been tried for years.  The theory was to let the ball get started without jumping the rifling.  Ned Roberts book says the shooters saw no real advantage to it.  I would wager that the twist at the muzzle has the most effect on accuracy.  However, that is why they make chocolate and vanilla so we can all have a choice.  If a gain twist barrel gives you confidence in your rifle, then you will shoot better. 

[Longknife]

I had an original Ohio made rifle rebored and rifled by Hoyt in the early '80's. It was bored to .40 with a 1-60 to 1-40 gain twist. I won many local shoots with it and nearly decimated the local squirrel population (HA)! It didn't seem to care about the powder charge. My 13 year old son was shooting it at a local shoot and on  split the ball with a dozen perfect hits the score keeper said, you can stop now, you have beat every one else. It sure was (is) accurate. I still have it....Ed

[WadePatton]

Trajectory has nothing to do with rifling.  It is a function of projectile speed vs gravity.

Right-o.

The only way I can see gain twist "affecting" trajectory is if it allowed good accuracy with a larger charge of powder. More powder, more speed.  Time of flight is everything when thinking of trajectory.  It is time reduction that flattens the curve.

And I learned in the last go around we had on gain-twist that while GT didn't really show an advantage over constant rate rifling, both were better than declining rate rifling--such that a tiny amount of intentional gain twist would ensure that a barrel didn't have declining rate at the muzzle (which could happen with the variables and tolerances in hand-machine work).

That's all I know about that.   

Learn to embrace and allow for the rainbow our ball spinners produce is my approach.

[Dan]

Dunno it's relevant, but the old battleships had gain twist in their 16" squirrel rifles.  Their trajectory was amazing at max range, but they were breathtakingly precise with placement in my experience in Nam.

[bob in the woods]

I was informed by whom I thought of as a very knowledgable shooter, that gain twist was much better served by an elongated bullet , the benefit being an increase in velocity for a given charge of powder over that of a constant twist barrel .  Example-  .45 cal  with a constant 1 in 18 twist vs .45 with a gain twist increasing to 1 in 18 approaching the muzzle.   There would theoretically be less barrel time and therefore less drag which would be beneficial to both the bullet and the barrel.   We are talking nuances here of course. I have no idea as to the practical application, however I have used my long range .45 cal muzzleloading bullet gun to shoot round balls , and the 1 in 18 twist requires small charges to give decent accuracy. I suspect that a gain twist would let me increase the charges and maintain the accuracy with increased velocity. 
One other thing. I have a rifle which has fired thousands of rounds [ .54 flint ] and when the accuracy began to diminish, I checked the bore and found some barrel wear in the area right where the ball would be seated on the powder. An increase in the powder charge brought the accuracy back, however I wonder if having a gain twist would result in less wear in that area ?   So many questions.....so little time 

[Bob Roller]

N.G.Whitmore,maker of the superb Grant rifle used a gain twist and according to Ned Roberts his
barrels were considered as unfair competition.The published data on the Grant rifle which is a light
offhand gun of 38 caliber said that the first 10 shots would have hit the lid of a percussion cap box**
at 110 yards.It used a picket ball which was neither bullet or ball and had a short bearing surface.
Harry Pope made a gain twist that was barely detectable such as a starting twist of one in 16 and
at the muzzle was one in fifteen and the quarters.Bill Large made a gain twist that was very accurate
and later,the barrels of Jim McLemore used this idea and is now starting production again and uses
Certified for Gun Barrels steel.Dan Pharis who is a contributor here has demonstrated McLemore's
barrel making on more than one occasion.One thing is certain with rifle barrels and that is this;
The last inch of the barrel determines the score on the target

Bob Roller
** Pope used a long bullet and the very slight gain at the muzzle WAS the determiner of the accuracy and it obviously works.
    I would think a long heavy 45 caliber bullet would work with this system but can only speculate on such a barrel with a more
    abrupt gain used with a ball that has little or no sectional density. 

[Hungry Horse]

 Bob’s got it right. I just examined a Charles Slotterbeck double rifle in .40 cal. That has gain twist stamped right on the barrel. It shoots a paper patched bullet.

  Hungry Horse

[Bob Roller]

Has anyone ever looked thru the barrel of a Colt 1860 44 caliber pistol.
The rifling looks like an  hallucination and appears to change directions
and I am  not talking about a reproduction either.
Bob Roller

[drago]

That's weird, I wonder how they did that?

[hanshi]

Around 55 years ago I ordered a .45 rifle and chose the "gain twist" option.  I'm not going to argue gain twist accuracy vs uniform twist accuracy.  What I can swear to is that that rifle is as accurate as anything I've fired since then.  Still have it.  Have a target somewhere around the house that I shot at 75 yards off a bench.  Other than that group I haven't fired anything similar to that group at past 50 yards since then.  That rifle took deer and bobcats and squirrel.

[Bob Roller]

Around 55 years ago I ordered a .45 rifle and chose the "gain twist" option.  I'm not going to argue gain twist accuracy vs uniform twist accuracy.  What I can swear to is that that rifle is as accurate as anything I've fired since then.  Still have it.  Have a target somewhere around the house that I shot at 75 yards off a bench.  Other than that group I haven't fired anything similar to that group at past 50 yards since then.  That rifle took deer and bobcats and squirrel.

Hanshi,
I am assuming this was a round ball barrel if you shot squirrels with it. Who made it?
Bob Roller

[Daryl]

Didn't Numrich turn out some gain twist barrels?

[hanshi]

Both correct.  The barrel was a Numrich Arms barrel.  The NA barrel on my flintlock was straight, uniform rifling.