Can you help me understand? The bore of my rifle seems to be tighter near the muzzle.

[Sooty Scot]

Running a tight patch from the breech to the muzzle, it feels progressively tighter over the last 1/4 to 1/3 of the bore. I'm satisfied that it's not fouling. I keep the bore polished as clean as possible; checking with a borescope.

I bought the rifle,used, in '19 reportedly 25+ years old but unfired. (It had been a decoration, reportedly over a mantle, but never fired. The pristine condition of bore and lock verified that to me.) The previous owner had desecrated (in my opinion and concurred on by the maker) the stock with brass tacks (poorly aligned).
I've removed these last set from the wrist since this picture.

It's a .50 plain Southern Mountain style,; made by Jack Garner. It's very accurate (as shown when fired by someone with younger eyes) but there's no indication who made the barrel. Since it's also, in my biased judgement, the finest rifle I've ever owned, I'm compulsive about taking care of it. I also want to know/understand all of it's quirks.

When I first noticed this "tightening" effect, I assumed it was just a characteristic of this rifle - maybe common with his rifles- but then read of progressive rifling in recent discussions rifling. I've been shooting various BP guns for many years but realize, reading threads here, that I'm still shamefully ignorant.

Thanks for any information you can offer.

Searching past threads, I found conflicting descriptions of this progressive rifling. Can you clarify this for me.

 

[nhmoose]

Progressive rifling is when the twist gets faster from the breech to the muzzle. What you are seeing is not that.

You are seeing a choked bore, that is when the muzzle end of the bore is tighter than the breech. It gets made by careful hand lapping of the bore and is a lot of work. So, you have a very desirable barrel IMHO.

 

[Frod733]

There is also progressive depth rifling. Some CW era muskets had that.

 

[SDSmlf]

Running a tight patch from the breech to the muzzle, it feels progressively tighter over the last 1/4 to 1/3 of the bore.

May be a choked barrel, but with the last 1/4 to 1/3 towards the muzzle getting tighter, more likely a tapered bore, possibly with an additional slight choke at the muzzle. GRRW and Bill Large barrels come to mind, but working on memory here and there may be other contemporary barrels made similar. Do you know who manufactured the barrel? Check the bottom barrel flat inside the stock.

 

[Grenadier1758]

@nhmoose is correctly describing your rifles barrel. It is a very desirable and likely very accurate on target.

 

[Sooty Scot]

Progressive rifling is when the twist gets faster from the breech to the muzzle. What you are seeing is not that.

You are seeing a choked bore, that is when the muzzle end of the bore is tighter than the breech. It gets made by careful hand lapping of the bore and is a lot of work. So, you have a very desirable barrel IMHO.

Thank you.I hope so.
I recall reading or hearing about a "choked bore" and wondered if it might be but, when I searched on that, all that came up were references to shotgun chokes of various types and discussions of their use when hunting with slugs.

 

[Sooty Scot]

May be a choked barrel, but with the last 1/4 to 1/3 towards the muzzle getting tighter, more likely a tapered bore, possibly with an additional slight choke at the muzzle. GRRW and Bill Large barrels come to mind, but working on memory here and there may be other contemporary barrels made similar. Do you know who manufactured the barrel? Check the bottom barrel flat inside the stock.

There are no hidden markings. About the only thing I haven't had apart ( to check, clean and polish) are the touchhole insert and the breech plug. The touchhole works well, so no need to play with it and I know better than to mess with the breech plug.
I'd love to know who made the barrel but since I bought it at a fellow attendee, who I met waiting for the doors to open. It's my dream rifle and I was smitten as soon as I saw ans got to shoulder it; too excited at finding it - and being able to come up with the cash- that I neglected to remember or write down his name.

Wish now that I had; he might have been able to answer some of these questions. ( It's taken me over 3 years to discover which ones I should have asked.)

 

[SDSmlf]

You may want to contact Tennessee Valley Manufacturing, the company that Jack Garner started and sold, and see if they know what barrel manufacturers he used back in his building days. I seem to remember seeing one with a Green Mountain barrel, but have to think he used more than one barrel manufacturer. If Bill Large barrels were used it could explain your ‘tapered’ bore.

 

[EC121]

Jack used some Green River barrels that had a tapered bore.

 

[MedicMike3762]

My wager is a choked barrel! I had a bill large barreled gun that I believe was choked, really tight on the short start but after that loading was a breeze and you could stay shooting for a long time before swabbing the barrel.

 

[Sooty Scot]

You may want to contact Tennessee Valley Manufacturing, the company that Jack Garner started and sold, and see if they know what barrel manufacturers he used back in his building days. I seem to remember seeing one with a Green Mountain barrel, but have to think he used more than one barrel manufacturer. If Bill Large barrels were used it could explain your ‘tapered’ bore.

That's a good idea, thanks.

The longer I dig & ask questions, the more questions I learn to ask,

 

[Sooty Scot]

My wager is a choked barrel! I had a bill large barreled gun that I believe was choked, really tight on the short start but after that loading was a breeze and you could stay shooting for a long time before swabbing the barrel.

Your experience describes my loading experience with this one - except that, unless I'm using .480's, I feel the need to swab after the third shot.
I've only put about 200 balls through it, so, from other things I've read here, it may well still be settling in.
I'd really like to believe that it is either taper or choke rifled - which hardly makes for objectivity.

 

[Bassdog1]

I find this post very interesting. I bought a new unfired TC 45 Seneca Barrel that has the exact same characteristics. I have not got to shoot it much but could not understand the tight fit at the last 25% or so of the barrel. Have several TC Guns and never experienced this before.

 

[Rifleman1776]

You are seeing a choked bore, that is when the muzzle end of the bore is tighter than the breech. It gets made by careful hand lapping of the bore and is a lot of work. So, you have a very desirable barrel IMHO.

Yes likely choked. But desirable? Opinions will vary. I wouldn't want it.

 

[GREENSWLDE]

Quite nornal. A decreasind depth accounted for Gas cutting.Tapered bores egzised Long before choke boreing. EVEN the Poor old British Enfield P53 had decreased depth rifling. Originals always did and still shoot acurately out to 6/7/8/900yd's. Ask David or the russians.. OLD DOG..

 

[M. De Land]

Running a tight patch from the breech to the muzzle, it feels progressively tighter over the last 1/4 to 1/3 of the bore. I'm satisfied that it's not fouling. I keep the bore polished as clean as possible; checking with a borescope.

I bought the rifle,used, in '19 reportedly 25+ years old but unfired. (It had been a decoration, reportedly over a mantle, but never fired. The pristine condition of bore and lock verified that to me.) The previous owner had desecrated (in my opinion and concurred on by the maker) the stock with brass tacks (poorly aligned).
I've removed these last set from the wrist since this picture.

It's a .50 plain Southern Mountain style,; made by Jack Garner. It's very accurate (as shown when fired by someone with younger eyes) but there's no indication who made the barrel. Since it's also, in my biased judgement, the finest rifle I've ever owned, I'm compulsive about taking care of it. I also want to know/understand all of it's quirks.

When I first noticed this "tightening" effect, I assumed it was just a characteristic of this rifle - maybe common with his rifles- but then read of progressive rifling in recent discussions rifling. I've been shooting various BP guns for many years but realize, reading threads here, that I'm still shamefully ignorant.

Thanks for any information you can offer.

Searching past threads, I found conflicting descriptions of this progressive rifling. Can you clarify this for me.

View attachment 140541View attachment 140543

A simple plug gauge will tell if the bore is choked. Often times a bore will have tight and loose spots in it and a plug gouge will reveal these as well. The bores can be tapered as well as choked both of which is formed by lapping. Pope liked tapers , others like Warren and Brockway felt a level bore into a choke was the better way to go. Both were superbly accurate bore configurations. The top of the lands are what is being measured which is the bore diameter. Nice looking rifle !
A gain twist will also make a tight patch more resistant to push through.

 

[hanshi]

A "choked" bore isn't all that UNcommon and is still in use today for certain revolvers. The revered Python has a choked bore and many older muzzleloaders often had them as well.

 

[Eric Krewson]

I have a rifle with a Bill Large barrel that is choke bored, it is my most accurate gun.

 

[rich pierce]

Very rare for the slight choke in a choked rifle barrel to extend further than a short starter leg extends. Usually only an inch or two. Probably a fortuitous chance happening.

 

[doubleset]

Could it be simply vacuum in the barrel when you get it closer to the top? With my .32, I was initially puzzled by this same phenomenon and thought it must be narrower at the muzzle. But I finally figured out that -- definitely with the nipple in -- there was significant vacuum built up by the time I got the jag up to within about 4" from the top. If I just stopped there and waited for a few seconds, and then continued, the "tightness" seemed to disappear. If your jag/patch combination is quite tight, this would exacerbate such a problem. Reducing the diameter of my jag helped things quite a bit. I confess I never had the problem with the .50 Lyman GPR I inherited from my son.

Is it the same with the nipple in and the nipple removed? If it's different -- even just to some degree -- that points to a vacuum issue.