Chamber at breech problem?

[Brad Foust]

Hi Friends, I am long into black powder but have been experienceing a problem that I would like some opinions on?
I have an Issac Haines rifle I built from a Dunlop kit at least 20 years or so ago. It has been a great rifle and I use it all the time. Have now killed many more deer with it than all my high powers combined.
Problem is, there seems to be a space at the botton of the barrel against the breech plug. When I run a tight patch down on a cleaning jag, right at the bottom it seems to release. Like the bore diameter gets a little larger?
Also, about this same time I am noticing this, my rifle seems to not shoot as accurate. Not near as good of groups. I have been trying to tighten these groups a couple years now, and it is not my inagination.
Thing is, I have never let this rifle dirty. It has always been perfectly cleaning and oiled.
Tjhe ONLY time I can think of is during the deer season here in Pa I will load it clean and use a good bore butter on a patch. And if I do not fire it I will let the charge in the barrel. But if I should fire it and re-load during a hunt, I always would unload and clean that evening. NEVER let a charge in a dirty barrel.
So why should it develope a "chamber" type space? And is there a fix?
Could that even effect the accuracy?
Thanks All

 

[CoyoteJoe]

I can't imagine why it would develop a chamber if it was not originally bored that way. Most antique guns will be more corroded the last few inches at the breech because they were not properly cleaned. This is especially true of shotguns or farm guns, they'd fire it, reload it and then maybe wipe it a bit but never pull the load to clean all the way to the breech. But you say that is not the case with your rifle so I don't know. That would certainly effect accuracy if the oversize area extends to the ball seat. If it's only an inch or so then the powder charge would occupy that area and the patched ball would be above it. So I guess it depends on the actual load. I'd try dumping some corn meal or Cream O Wheat atop the powder to occupy more space under the ball and see if that helps.

 

[Robby]

The term "ring the barrel" comes to mind. It is formed in the barrel when a ball is not seated all the way down. Is it possible that you fired it with the ball ahead of the powder charge? The only way I can think of it affecting your accuracy is if the ring is right at the area of the seated ball. Then possibly you are getting an uneven blow by and pressures. The corn starch might lift the ball past that area. There are two schools of thought on shooting a barrel with a ring. Some say they have used them for years and have had no problems, others say, get a new barrel. Good luck!!
Robby

 

[Rifleman1776]

Like others, I'm puzzled.
Get a good bore lite and take a look.
Despite cleaning you may have a carbon ring build up. Soak with hydrogen peroxide and give a good scrubbing.

 

[jdkerstetter]

If you really want to know for sure what is going on and don't feel confident at handling the work yourself, I recommend Brad Emig at Cabin Creek Muzzleloading. He is a master blackpowder gunsmith and is on your side of the river just off U.S. 30 in Hellam, just the other side of York.
http://cabincreek.net/

There are some competent 'smiths in your area also. Old Bedford Village Museum can probably put you in touch with someone....but nobody of Brad's caliber.

Good Luck, J.D.

 

[M. De Land]

I think I would pull the breech plug and have a look see myself. I have never cared for powder chambers because it's to hard to get them cleaned out perfectly and as far as I can see they have no real advantage. Course your kind of stuck with a powder chamber in patent breech designs to some degree. MD

 

[pargent]

If you have used this gun a lot it could be errosion , I had read some where that this can occour with heavy use ,if I recall correctly the author cut the worn section off and rebreeched the barrel.

 

[Robby]

Bigmon, Whatever it is, I hope you will post your findings. Things that affect accuracy are always of interest and good to know. Good luck!
Robby

 

[jerrywh]

Take a Michrometer reading on the outside and see what you get. That will tell you if the barrel is ringed Vs. Corrosion or boring problems. Then, Like the other guy said, pull the breach plug and have a look. I don't like corn meal personally. I would rather try lubed felt wads. If a barrel is bulged or as they say ringed It has been subjected to pressures beyond the yield point. That is very bad. Consult Zonie, he's the engineer around here.

 

[M. De Land]

I've not seen a barrel ringed in the breech area but I have personally ringed a .50 up at the last eight inches of barrel near the muzzle. If it's ringed you can usually see it from the outside just looking down the barrel in good light.
I cut it off to 20 inches and tried it out but accuracy was gone never to return.
The trouble with cutting off to the rear is the tenons won't line up any more and if tapered or swamped the barrel mortice won't fit either.
The plug has to come out to tell anything for sure. I'd plug the nipple and pour in some liquid wrench and stand it in a corner for a week.
After that,use a good vise with felt pads to hold the barrel and make yourself a snug fitting breech plug wrench, put some heat to it from a propane torch(you won't hurt the steel or the finish with this heat source) and it should come right on out.

 

[Dphar]

I can imagine several things than might cause this.

Pull the breech and LOOK at the barrel carefully.
If it IS enlarged and there is no visible reason, no sign of corrosion etc I would seriously consider replacing it. Afterall its right next to your face.


Dan

 

[jdkerstetter]

I'm curious. If it is enlarged and there are no visible/measurable reason, no signs of corrosion and it was not this way originally...not manufacturer induced...then how? :idunno:

Thanks, J.D.

 

[Robby]

Jd, If the ball was short seated with a sizable gap between it and the powder, upon ignition the pressure wave halts, expands and moves on as the ball gets under way leaving a ring, much like a dent, behind where the ball was mistakenly seated. Depending on the barrel this may not be detectable visually or measurably from the outside.
I'm with Dan and would replace the barrel.
If that is indeed what it is.
Robby

 

[jdkerstetter]

Didn't know that. I assumed there would be some way to determine a bulge in the bore by measuring outside diameter. Interesting.

If the OP is not comfortable doing this inspection himself, I really think he should contact Brad at Cabin Creek. He'll let 'em know the correct path to take. But something has to be done, for sure.

Thanks, J.D.

 

[jerrywh]

If the barrel is ringed it will be measuable on the outside. A ring is a bulge.

 

[Robby]

Jerry, I have only had to deal with this once. It was a 3/4" across the flats, .32 cal.. Measuring the flats for an area of about two inches around the ring, I could find no measurable difference, but I could see the ring clearly. I concluded that material must have been displaced before and aft of the ring, which I also concluded it must be somewhat more like a dent than a bulge. I think with a larger bore, higher charge and heavier ball, that a bulge would be measurable as well as seen. Just my experience, for what its worth. I did replace the barrel.
Robby

 

[pargent]

A thing you ca try is to load your normal powder charge then and some filler ( you will have to work out how much to position the patched ball clear of the worn section with the ball seated firmly ) if your group size shrinks you have errosion at the first section of the bore. This is considered normal wear for a barrel that is actualy used alot. History records this as the case and modern target shooters do as well, if the rifleing is still ok rebreach if worn to much new barrel, or put up with the larger group sizes. Micing the barrel OD will show no difference if this is the case , I am also assuming that you would remember the recoil if the barrel was pressure ringed from the inside

 

[Dphar]

I'm curious. If it is enlarged and there are no visible/measurable reason, no signs of corrosion and it was not this way originally...not manufacturer induced...then how? :idunno:

Thanks, J.D.

Given the "quality" of the steel used in many American ML barrels anything is possible. Maybe the steel simply flaked away. I have seen this occur is a 45-70 barrel made from cheap steel by a well known maker of barrels in Montana.
In any case I would wonder why the thing is suddenly noticeable and revert to the "this is inches from my face and contains 1000s of PSI" thinking.
Like the sign in the Costco deli states "if in doubt throw it out".
Dan

 

[jdkerstetter]

I won't argue with you there Dan. That's why suggested he take it over to Brad Emig and have checked out, if he is not capable or comfortable doing it himself.

Why take unnecessary risk? Enjoy, J.D.

 

[Birddog6]

Possibly the barrel was bored that way originally & he didn't notice it. I have had several barrels with Loose Spots in them. One was about 8" from the muzzle, 2 were in the middle, 1 was about 8" from the breech.

I am told this is caused by power surges or intermitten power to the reamer while reaming the barrel. I don't know...... as I don't bore & ream barrels, this is just what the barrel manuf. told me. In all occasions, the manuf. replaced the barrels for me free of charge.

I would unbreech it, clean it well. do some careful examination of the bore.

No Way would I use that barrel like it is, because you Don't Know What Caused The Problem. And I would send the barrel back to the manuf. & ask them to access the issue.

If it is Bulged or Ringed, you should be able to hold the barrel to a light & lay a flat edge across the flat & see the problem. Holding the bore to a light, you may be able to see the distortion in the bore at the problem area.

Keith Lisle