Gain twist?

[wyldwylliam]

Hey Gents, I recently got hold of a reprint of the 1865 Henry brochure and in it there's a report from the Ordnance Board which states that an 1862 test by them shows that "The twist of the grooves increases from 1 turn in 120" to 1 turn in 33" at the muzzle."

This is the first I've heard of this, I didn't realize that the originals had gain twist, if in fact this report is correct.

Any comments?

[wyldwylliam]

Nobody? I would really like to know it this report is accurate, as to go from that slow to that fast in 24" seems pretty radical to me, and am also wondering how much better the old rifles grouped than today's repros, if at all.

[Tascosa Joe]

I have only been close enough to touch one real Henry, and it had been drug around by 2 little boys and played Cowboy and Indian with for several years.  Because of the location, and the families history with the area, the rifle could have been present for the Sand Creek Massacre.  But I degress from the subject,  the only way we could know on this forum would be if someone who has an original could prove or disprove the presence of gain twist rifling.  I do know that Colt pistols from this era did have gain twist rifling.

[sail32]

Grain Twist was popular in England. The last production rifle that used it, that I am aware of is the 1891 Italian 6.5×52mm Mannlicher-Carcano rifle.

[Sir Charles deMouton-Black]

If your question is whether the Henry has gain twist rifling, I don't know the answer.

I purchased a Hi-Wall years ago that required re-boring.  I had a barrel maker, Ron Smith of Alberta, Canada, do it in .376 gain twist for the 38-55 case.  The result is remarkably accurate, but I can't say that gain twist is more accurate than a constant twist with the appropriate rate of spin.

[wyldwylliam]

Thanks much for the replies, Gentlemen.

Yep, the question is, did the originals have gain twist?

The test results I cited in the op are the only place I've read this assertion, including anything I've seen online or in Les Quick's book. All he says is that they had six lands and grooves with a few in 5x5.

You'd think that if the originals did have gain twist it would be more widely commented on, although most serious collectors I've known are more interested in the external aesthetics than the arcana of the internals.

In any case, several reports I've read from the field during the CW commented on superior accuracy of the Henry, so perhaps that Ordnance Board test result is true.

[Arizona Trooper]

I looked down the bore of one a couple months ago, in the 9K sn range. Wasn't looking for gain twist and didn't really notice it. If it had gone from 1 in 120 to 1 in 33, seems like it would have been pretty noticeable.  I looked down the bore of a '66 carbine in the 18K sn range just this evening and it was for sure constant twist. 6 grooves, 1 in 33 would be close on the twist. Burnsides are the only Civil War breechloaders I know of that have gain twist (other than pistols). Not the best shooters, but not bad either.   

[Coffinmaker]

I would personally see no reason to doubt the Ordinance Board findings.  Traditionally, the Board reported the result of their inspection and whether the weapon met performance requirements.  Opinionated Generals decided whether to buy or not.  Most stuffy old Generals of the day considered a repeating arm to be a waist of ammunition

Coffinmaker 

[wildman1]

I'm not sure if gain twist is effective or not. However, It would by no more radical a change to go from 120 to 33 than to start at 33. My resoning for that is the bullet is not moving (twisting) at all until it is fired. In a twist rate barrel of 33 it will go from 0 twist to 33 twist instantly. In a gain twist barrel the twist will start at 120 and go to 33. Theoretically sounds like it would be easier on the bullet. WM

[Grapeshot]

Grain Twist was popular in England. The last production rifle that used it, that I am aware of is the 1891 Italian 6.5×52mm Mannlicher-Carcano rifle.

The 25mm Bushmaster Chain Gun mounted on the Bradley and The Marines' LAV have gain twist barrels and are very accurate.