hex bore

[brucegodlesky]

 I recently come across and old barrel, badly rusted. It appears to have a hexagon bore, while the barrel itself is octagon. is this something common?

[Daryl]

That would be strange from those I've seen.

[rich pierce]

Some times when freshing a barrel they left things looking like flats in the bore rather than landscape grooves at the muzzle. I’m not sure if they were filed this way. Have you looked further down the bore to see what the rifling looks like a foot or more down?

[Ky-Flinter]

Could be Whitworth hexagonal rifling.

Ron

[Hungry Horse]

 Since we’re all making guesses, here’s mine. I suspect its a rifle that originally had wide lands, and narrow grooves in the bore. These were quite common in the past. But, if the lands get rusty, or damaged, and somebody try’s to resurface them it’s pretty easy to cut the lands down so much that the grooves almost disappear, making it look like a hexagonal bore.

Hungry Horse

[Tanselman]

Hex bores, i.e., 6-groove rifling, was much less common than the standard 7-groove rifling, but it was used in several states including Ohio, Indiana, and Kentucky that I am aware of. The Bardstown guns from Nelson County, Kentucky, by two of Kentucky's best makers, Jacob Rizer and David Weller, all had 6-groove rifling during the partnership period of 1815-1826, and they were considered one of the best guns made in Kentucky and very accurate. When Weller left the partnership in 1826 and moved to nearby Hardin County, he took the 6-groove rifling bench with him based on his later guns, and Rizer's shop went to 7-groove rifling on all his later rifles.

I've heard theories that an odd number of grooves makes sure a land is across from a groove, which "theoretically" pushes the patch into the groove better. If that were really true, seems odd that two of Kentucky's best gunmakers would use even-numbered rifling for eleven years right in the middle of the heyday of Kentucky's best riflemaking. 

Shelby Gallien

[Karl Kunkel]

The theory I heard was that an odd number of grooves meant there was a land opposite the groove which aided in backing or supporting the cutter during the rifling process.

[Carl Young]

I agree with Karl I was taught barrel-making by a Pa. gunsmith who learned how to make every part of a longrifle in the 1920's on hand-powered machines. I also heard this from Phil Orem, a NMLRA benchrest champion, and scientist who I made several award-winning barrels for.

The theory I heard was that an odd number of grooves meant there was a land opposite the groove which aided in backing or supporting the cutter during the rifling process.

[Tanselman]

With old narrow rifling grooves and cutters, the lands were much wider than the grooves, so whether a full land, or two partial wide lands, were across from the groove, there was a lot of support for the cutter either way. I could see the merit in that argument if rifling grooves were wider and lands narrower as in modern rifling, so a full land would help the cutter. But with older style, narrow groove rifling with lands much wider than grooves, I can't see how the "opposed lands and grooves" would make much difference. I'd think back then there were probably different theories and opinions on what was best, not all experienced gunsmiths agreed on what was best, and that's why we see some even-numbered rifling in some good quality longrifles.

Shelby Gallien

[Tanselman]

I just got back a heavily used, but well-made Moses Dickson half-stocked rifle from Louisville ca. 1840s that had some lock work done. I'd never looked at the muzzle that closely since the gun went west and shows a lot of wear, but it has survived with no major damage or alterations and came out of the far west. When I checked the bore last night, I was surprised to see it had 6-groove rifling, worn but still visible at the muzzle. Most of his guns have the "standard" 7-groove rifling we usually see. Moses Dickson was Louisville's premier gunmaker for many years, sold locally and sold to Ohio River traffic coming down river and heading west... so this was probably a gun purchased by a river traveler heading west.

Dickson's guns were held in high regard inside and outside of Kentucky, to the point John C. Fremont stopped in Louisville to purchase 8 rifles from his shop at the start of Fremont's 3rd Rocky Mountain trip... and in 1845 those guns sold for $35, $40, or $45 depending on furniture, i.e., iron, brass, or silver. All were half-stocked rifles with patent breeches. Just seems odd that Dickson's shop, then called "Dickson & Gilmore," would provide both 6 and 7 groove rifling in different guns from the same shop in about the same era.

Shelby Gallien