Note this simply a discussion of how I see this at this time.
Uncrowned muzzles like this one I assume.
This is from an apparently unused Leman Flintlock with a lock dated 1840.
We must look (as well as we can) at what the muzzle really looks like.
If we look at this photo we cans see the edge has been broken enough to allow a ball to be started. "Funneling" may or may not be present but it was not significant if it was funneled.
Without a crown or some form of "breaking the edge" at the muzzle it is impossible or very difficult to start even a patch on a jag. But it takes very little to get this done in reality.
So I think we are talking a matter of degrees rather than having a crown vs absolutely no crown. Its impossible to load a sharp edged muzzle unless it is larger than the ball/patch. But even a slight angle or rounding of the edge makes a it possible.
This is not the same as the Leman obviously:
But this is a two angle crown cut with 2 different tools. It is intended to start a fairly/very tight ball/patch fit. I am not sure that the early rifles always used this tight combination.
But then they often used a much different rifling form that is used today as the Leman muzzle indicates. The Leman will load almost like a smoothbore and will require a small ball and thick patch or a thinner than normal patch to load easily.
Those who shoot smooth rifles etc already know that the smooth bore 50 caliber, for example, will not load the same patch ball combination as can be loaded in a 50 cal rifle that has grooves equal to or wider than the lands.
In "Hawken Rifles" Baird describes the interior of the barrel of a Hoffman & Campbell marked Hawken. The funneling is far less it seems than what many "moderns" do:
"Of 50 caliber, the bore is a slight taper from the breech to a point about 9 1/2 inches from the muzzle. Here a choke is apparent for about 8 inches, then from there to the muzzlea slight flaring is seen. Measuring approximately .0005, about 1/4 inch from the end of the barrel, this flare suddenly increases another .002, ..."This looked like "rod wear" but was not since is was uniform around the bore. Nor does Baird tell if the measurements given are .0005 per side or .0005 total. I expect it is per side. .0005" total is not much difference. So I assume, and thats all it is, that by .002" he means .004 total. But both the men involved with testing the rifle are gone now.
This treatment could be used on a barrel and would be difficult to detect unless very careful inspection were made.
This is an original J&S Hawken muzzle (sorry for so much Hawken stuff but this is the information I have access to right now) on the BBHC web site, while its pitted it does show some form of crown, the edge of the bore has been rounded or "broken". There is no way to tell if it has the choke and funneling mentioned above.
http://www.bbhc.org/collections/BBHC/ImageViewer.cfm?object_key=22284&img=canon1d2005%2F1997.4.2v7.jpgThe Hawken rifling, from what I have seen and from a written description by Bill Large, was more modern in form than the Leman shown or the 6-7 sided bores found on some rifles of the same period. This is Whitworth like, usually with wide flat lands with a small groove at each corner.
Rifling form may have an effect on how the muzzle was relieved. It would be more difficult to "funnel" a flat sided bore than a round one I would think. But it could be done with files or with the tool that cut the rifling.
The deep funneling, IMO has to effect accuracy, but this would need to be tested extensively before and after funneling to make any statements other than "I think". This said "I think" that excessively large muzzles will allow gas escape past the ball. If this occurs and the gas has any significant velocity it can cause he ball to leave the muzzle uncentered. Gas velocity past the ball can cause it to move to one side or the other if there is greater escape on one side or the other.
But the speed of the ball may be such that the ball is not effected.
Someone with the time needs to shoot 10-15 pounds of powder in 2-3 barrels and see what occurs.
My idea on funneling is that I have never seen the need to do a deeper crown than shown on the Green Mountain barrel shown above after its proof load. In fact this is the deepest crown I ever did.
There are wide variations now in how muzzles are done and I am sure there were wide variations in the past.
Dan
