Different ML barrel profiles...why?


October 24, 2003, 12:20 AM
I was looking around at the different ML types available and I found quite a few different barrel types. Some round, some octogon. Even some octogon and then going to round.

During my shopping trip at Bass Pro Shops today I even found a couple of different barrel types on what I would consider the same era revolvers.

1851 Colt Navy= Octogon Barrel
1860 Colt Army= Round

Does anyone know why one barrel method was chosen over the other?

I would think that octogon barrels were a bit easier to manufacture from bar stock. But then that wouldn't explain the ones that started as round and then went to an octogon shape.

Anyone know why or have a guess?

Good Shooting

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October 24, 2003, 08:55 AM
The older muzzle loader bbls made in USA were made by winding a strap of black iron around a mandrel and welding into a tube looking sorta like a stick of peppermint candy by ye olde local blacksmith. Colt's forged all their stuff so they drove the hot metal into a die under heavy blows. I guess they had a better machine shop than the manually operated/water powered grindstones available out in the sticks.

October 24, 2003, 03:55 PM
I'm definitely not an expert, just tossing out ideas here, but I think its mostly for looks and maybe for weight in some cases.
Barrels seem to all come from a standard size blank, at least in the calibers I've been able to look at (.45 .50 and .54). Obviously you have quite a bit more meat left around a .45 diameter bore from a 1" diamerter blank than with a .54 bore. So there's some unneccesary weight there that you can get rid of if you want. So you put the barrel in a lathe and turn a taper into it towards the muzzle, wieghs less and looks fancy.
Since BP isn't a super high pressure propellant, I would guess that most barrels have thicker walls than is necessary. So makers change things around trying to improve looks, and possible barrel harmonics.

October 24, 2003, 06:08 PM
not pistols, but I read a book recently that included a contemporary advertisement or article from Sharps about their rifles. They strongly suggested the round-barrel version over the octagon on the grounds that it demonstrated noticably better accuracy. Dunno if it's true or 19th c. marketing copy, but apparently that was at least one school of thought of the day.

I'm guessing the "smooth and sleek" look also fed into the technical/industrial revolution mindset that was starting to take hold. Plus the weight savings.

Hrmm.. just a guess, but perhaps improving metalurgy allowed them to contain high pressures with less metal during that time? I know a lot of 18th c. and early 19th c. longarms had an octogon profile at the breech, then thinned out to a round barrel towards the muzzle. Perhaps the extra metal at the breech was thought necessary where the charge was set off, less so towards the muzzle? And hence, as metallurgy improved, octogon was discontinued entirely?


October 24, 2003, 07:38 PM
Thicker at the breech would make it easier to thread the breech plug.

October 26, 2003, 09:59 AM
And then there are the "swamped" octagon barrels, on some original guns and some modern custom muzzleloaders. They are octagon for their whole length, but taper from the breach to the middle and then get thicker again toward the muzzle. Swamping was/is done to reduce weight compared to a straight (non-tapered) octagon barrel, yet provide a bit of muzzle heaviness, to improve off-hand steadiness. There are a whole bunch of different swamp profiles too. Various thicknesses, lengths, rates of taper and flare, etc. Each maker used whatever profile he (or his customer) thought looked/felt right. Today's swamped barrels are usually made to duplicate the barrels made by some particular gunsmith or region of gunsmiths who are of historical interest.

One caution; some swamp profiles are really THIN in the middle, and should only be used on flintlocks. When a caplock goes off, it is a "closed" system, with the hammer holding the cap over the nipple and sealing the chamber/barrel. The only way for the gases to escape is out the muzzle. Flintlocks have an open hole in the vent where the "flash" went in, and where some over-pressure can leak back out.

4v50 Gary
October 26, 2003, 12:05 PM
Same reason why Colt fluted some cylinders: weight reduction.

As to rifles, swamped barrels do reduce weight so you can have a lighter gun with the same barrel length. It works and my second flintlock rifle (kit) has a swamp barrel.

Jim K
October 26, 2003, 10:37 PM
Round vs octagon/hexagon. Purely looks and customer tastes.

Colt used round barrels, part round barrels, octagonal barrels, then back to round again. By the end of the percussion era, changing taste and different manufacturing techniques put Colt firmly into the round barrel mode, but S&W, which forged their barrels and used a profiler, made several different shapes (and is still playing with barrel shape).


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