1803 Harper's Ferry Rate-of-Twist

[Trench]

Hello all. I just read on the Rifle Shoppe web page that the 1803 Harper's Ferry had a 1:49 rate of twist for calibers .573 or larger.

Conventional wisdom today seems to imply that a rifle of this caliber would have at least a 1:70 twist. What do you guys think was going on here in the design of our first military rifle?

 

[J.D.]

One turn in 48 inches, give or take, was a common twist in old guns. Faster twists provide good accuracy with lighter powder charges. Barrels with slow rates of twist seem to need heavier charges to shoot well.

 

[Trench]

It's true that faster twist barrels like smaller charges. I also read that the standard charge for the 1803 was 70gr of powder. That's the same as my 1:48 twist "Hawken". Perhaps the army would have chosen this faster twist to conserve powder?

 

[MJuingong]

IIRC, I have read that ramming a comparatively tight-fitting ball down a rifle barrel produces more wrist and hand strain than ramming a loose-fitting ball down a smoothbore. That strain could affect accuracy. So, a slower twist could produce less stress in wrist and hand than a faster twist.

 

[CoyoteJoe]

In 1803 the relationship of rate of twist and caliber of ball was not really understood. Most barrel makers had just one rifling guide which they used for all barrels regardless of caliber. The "best" twist was a mater of personal opinion among gunsmiths, each likely believed his twist was best even though he may not have known exactly what twist his guide would cut. Same with the width, depth, number and shape of grooves, everyone had their favorite form of rifling which they believed best.

 

[tsmgguy]

And, the British Baker rifle had a 1/2 twist in 30", and shot well with round ball and about 85 grs. out to 300 yards. Go figure.

 

[piteruu]

Baker rifle had a 1/4 twist in 30" (not 1/2).

 

To my knowledge, the Harper's Ferry 1803 rifle was never made in .575 caliber, so how could this have been the origional rate of twist for this rifle in this caliber?

A half dozen myths and wives tales about something that never existed in the first place?

 

[Johnny Tremain]

Concur

The few originals are 54 cal.

As the barrels wore, they retooled the bore to 58 cal circa late 1850s.

Funny thing is that Jessie himself told me that.
Being that he has held and measured the few originals.

 

[tsmgguy]

So, could we say that a little twist is a good thing, and may be all that's necessary? And, a lot of twist is probably unneeded, promotes fouling, and make the rifle harder to load when fouled?

 

[tsmgguy]

Wrist and hand strain effecting accuracy? I guess I better get that hernia fixed or my TV reception will be poor this evening! :grin:

 

[Dphar]

Twists faster than 48" will start to cause trouble with high velocity loads.
But going too slow can result in needing a lot of powder to shoot well.
Remember the military was not using a lot of powder in the 1803. Lewis & Clark calculated the weight of their lead powder containers to weigh twice what the powder they contained would and this included priming. A 49" twist will allow 90-100 grains of powder in a 54 and this will do anything the ball weight is capable of.

The "short rifles" carried by L&C were identical to the 1803 HF for practical purposes, or so I have read.

Dan

 

[Dphar]

Surviving rifles, if used very much, were likely re-cut or "freshed" to larger bores. I think the one at the Cody Museum is a 58... now. What a 18th/19th century ML rifle is now is not necessarily what it was when it as made. "Freshing" or re-rifling etc was common practice. Freshing will usually increase the bore at least .02" making a 54 into a 56.

Dan

 

[MJuingong]

tsmgguy:
I think the title was "From Flintlock to Rifle", Author was "Ellison"? printed in the late '70s?
Boy, my memory is going..
At that, I'd better check my hernia too. My TV has been a bit fractious lately.

 

[tsmgguy]

"The "short rifles" carried by L&C were identical to the 1803 HF for practical purposes, or so I have read."
________________________

I have ordered a Lewis and Clark rifle from Jess of The Rifle Shoppe after a phone conversation with him about the guns. He's pretty sure that he can produce an exact replica of one of the 15 pieces procured by Meriwether Lewis at Harper's Ferry and carried on the Expedition. He says that these were not first pattern M1803 rifles.

It'll be most interesting to see what shows up on the door step six months or a year down the line! All I know for certain is that the quality of his offering will be excellent!

 

[Dphar]

Doing some more research it appears that there were no prototype 1803s. At least no documentation.
All we really know is they were "short rifles".

Dan