The best 32 cal RB twist ?

[Johnch]

Since I just about can't use iron sights for hunting any more
And IMO a scope just looks wrong on a side hammer front stuffer ( I have 3 )

I am thinking of ordering a barrel to shoot 32 RB's and build a inline around it as a winter project

I looked at Green mountain barrel web site and they only list 1-48" twist

A better twist ?
A better barrel ?

This is just in the ordering a few parts stage

I will have to wait till work slows down for me to get serious about making parts

Thanks for the input

John

[JeffinNZ]

1-48 is just about spot on for .32cal. The smaller the ball the faster the twist. That's why .62cal have a twist of 1-72 or less. You'll find all the major MLer barrel makers are running 1-40 something for .32-40cal RB.

[northmn]

I have used both the newer 1-48 and the 1-66 in the old Douglas barrels. Both worked and both required a charge of about 20 grains or better to get the best accuracy, usually about 25 -30. I kind of lost interest in the 32 because of that. It would hit at small game ranges about like a 22 mag hollowpoint and was more destructive than I liked so I switched to a 40 which bucked the wind better. 32's are still fun. Ideally I think a faster twist, such as a 1-36 would be better for a 32 but would not pay the dollars necessary to get one. An interesting project would be to buy a 32 slug barrel and try that with bullets.

Northmn

[Digital Dan]

Round ball stability is something worried about way too much. General rule of thumb, 100-120 x Diameter will give the twist needed. Faster won't hurt....

[curator]

1 in 48 is the Greenhill twist for a .32 round ball. Years ago I had a nice Pennsylvania .32 long rifle with a 1 in 56 twist. It shot OK but my T/C Cherokee with 1in 48 would shoot more accurately. These "small-bores" are really picky about bullet quality, and patch lube/thikness issues. Once you find the correct combination, they are great fun for small game out to 75 yards. Whistle-pigs and tree rats look out!

[Digital Dan]

Probably this would be a good time for me to admit to minimal muzzle loader experience and a bit more with BP here and there, not a shred of it with small bore rifles. I do have a working knowledge of exterior ballistics and what it takes to stabilize a bullet. What is required of RB rifles is close to nil.

What the issue is with gyroscopic stability goes directly to the matter of displacement between Center of Gravity and Center of Pressure in the bullet. If there is none, such as with round balls, the only other necessity is to give the bullet a sense of direction in its rotation, else the ball will spin randomly and create spurious flow fields. Such chaos is not the stuff of accuracy; ask those who shoot smooth bore muskets. Virtually any rotation will suffice to provide stability in a round ball, but it is essentially consistency of aerodynamic forces that is required, not gyroscopic stability. As RBs and the forces created are highly variable due to small imperfections in a fired bullet, it is only necessary to create a uniform variability. A little spin'll do the job.

Given the formula I referenced above, my .45 flinter should have about 1:54 twist on the slow side or 1:45 if the "100" constant is used. It's 1:66 and shoots just dandy. 2" offhand at 50 yards for 5 shots...if I pay attention. I suspect 1:100" twist would also work. A fellow named Bill Crowley wrote in Muzzle Blasts many years ago of having a .50 caliber round ball target rifle with a 1:113" twist that was quite accurate. His 1/226 ratio would suggest a 72" twist suitable for a .32 caliber round ball rifle and I believe it would work well.

I agree with Curator: Patch and ball fit...along with a quality barrel are more important issues than twist, especially with small bore rifles. Some comment from time to time about finding success with increased charges. Maybe the thought is that faster velocity increases stability. Well, it does, but not much. More likely, what happens with small charges is the ball does not obturate due to low pressure. That leads to poor fit and probably gas cut patches.

My .02 worth....