Why octagonal "smooth" rifle barrels?

[Stumpkiller]

I had a sit-up-in-bed thought recently. Why make a smooth rifle with an octagonal barrel? The barrels of smooth rifles are fairly thick walled; enough to support rifling. Isn't this a waste of iron and an added complication in the bedding process, as well as a bunch of unnecessary weight?

I guess if a skelp is formed around a mandrel it is easier to hammer out an eight sided shape as opposed to a cylinder, but I'm no blacksmith. Is a octagonal barrel perhaps easier to inlet into a stock, or no different from a cylinder? Muskets were all round barrels at that time, so presumably it was a standard practice to shape a tapered cylindrical barrel. Certainly a thinner wall would have been practical? Was the metal quality low enough to require wall thicknesses 50% of the bore diameter

There is an ongoing argument that smooth rifles were possibly rifles that were shot out and/or opened out purposely to extend their life.

I got no answer here, it just struck me and I thought it worth a discussion.

 

Greenmountain 1" accross flats in 20bore,.62 cal. Been thinking of a early Lancastor smooth rifle in the barrel.

 

It is neither easier or harder to forge a piece round instead of octagonal. More than likely, swages were used for finishing but a round shape can be forged between two flat surfaces - just keeping rolling and hitting the high spots. I suspect it was easier to put sights on an octagonal barrel with hand tools as very few gunsmiths had lathes or mills. The barrels were hammered close and filed to finish. When twisting a piece of square, I put the piece in the vise and set two small pieces of flat iron on each end. It's easy to see if the sides are not in the same plane and square - the same can be done while filing. A round barrel only needed a front sight and precision was not mandatory. More meat in a rifled barrel also allowed it to be freshed out several times to larger calibers.

 

[Gary]

Methinks that the rifle was originally rifled, but as it wore out, it was bored smooth.

Wallace Gusler has one rifle that was made smoothbore when the individual was discharged from the rifle regiment and then went into a Pennsylvania Continental Regiment (musket armed).

 

[tg]

There are many "smoothrifles" that are in good condition and have no excessive wear to indicate they were originaly rifles and made smooth later also the term smoothrifle is use alongside the terms rifle amd smmothbore, in period writings, no doubt some were origimaly rifles but many seem to be made that way and some in such small cals. that would have meant the original rifled barrel would have been very small to result in a bored out smoothrifle of .42 cal. the heavy barrel of a smoothrifle be it round or oct was for the use of heavy loads of buck and ball according to some. The idea is a simple one a gun with front and rear sights, a cheekpiece, griprail all the rifles features made for accurate aiming,and keeping the ability to use shot, but lacking the slow loading feature of rifling.

 

Something to remember is that the heavier the barrel, the better it shoots round balls when a smoothbore. That has someting to do with barrel vibrations & harmonics.

 

[musketman]

Why make a smooth rifle with an octagonal barrel?

I can answer that, some people (myself included) just like the looks of an octagonal barrel...

 

Probably several reasons; rifle barrels were typically (but not always) octagonal; the smooth rifle may have been a rebored or shot-out rifled gun--or may have been made that way originally on purpose: it has been suggested that (besides the versatility of using shot, buck or ball)the smooth rifle was cheaper since it skipped the rifling step, which was time consuming and labor intensive.