Breech face fouling trouble

[Robby]

I have suffered no such maladies but would advise you not to do it.
Robby

 

[oldwood]

I've seen a number of originals with a vee filed on the breech plug face at the touch hole entrance. When the breech plug is near installed , I polish the face of the plug on the buffer , then install it. Nice to shine a simple light down the hole and see it's reflection in the breech face.

 

[M. De Land]

I'd think about the possibility of moving my touch hole liner back some, dish out and polish the breech plug face.
View attachment 129583
I just happen to be working on one right now.
Robby

That profile will be a thread, fouling loader, for sure. The reason for the inner barrel ledge and breech plug interface is to seal off the chamber pressure from blowing fouling into the threads. Any thread type, by itself is not a good gas seal, it needs a seat to draw up against to form a seal. The threads in the picture are wide open to fouling penetration. It is physically impossible to cut and fit any type of thread profile tight enough to seal off gas from penetration without a seat to draw into.

 

[Brokennock]

I think I'd bank on the experience I know @Robby has on this one.

 

[Brokennock]

One more thing I just thought of that I was doing but didn't mention before is leaving a pick (piece of soft iron wire of vent diameter) in the rent hole when charging to keep it clear

I do the same thing with my smoothrifle that has an internal cone vent liner,,, works like a charm. I have however noticed that it doesn't work as well with my gun that has the flash hole drilled direct through the barrel wall,,,, no cone.


I don't know if my question made it obvious, but, I am wondering if maybe it is possible that it isn't a build up of crud starting at the breach face and getting so thick that it blocks the vent. But, if maybe that crud ring some have trouble with where charge and ball meet is what is interfering with your vent hole.

Also, maybe try not swabbing between shots, at least just as a test to see if the problem goes away. Then, if it goes away, work on developing a load that meets your accuracy standards that doesn't need swabbing.

 

[oldwood]

Next time I go to the range ,I think I'll try leaving a soft touch hole wire in the touch hole and load the fouled gun to see how many shots I can get. Hummmm? Never thought of that.........

 

[Kevin]

On my patent breeched guns I got in the habit of running a damp patch on the cleaning jag while ramming the ball down. Fowling stays on the muzzle side of the prb. Pulled a few stuck balls till I started doing that. Not every shot, just when the fowling made it a little hard to load. Just a thought. On a flat breech, the humidity makes a big difference on the fowling.

 

[M. De Land]

On my patent breeched guns I got in the habit of running a damp patch on the cleaning jag while ramming the ball down. Fowling stays on the muzzle side of the prb. Pulled a few stuck balls till I started doing that. Not every shot, just when the fowling made it a little hard to load. Just a thought. On a flat breech, the humidity makes a big difference on the fowling.

I sure appreciate all the ideas and feed back. I'll post back when I get it all sorted out so we can all learn something from this. It probably will require a few more matches and trying different things. I may have to break down and cone the inside of the vent but I don't feel that is the cause as until around shot 25 it is reliable and feels nearly as fast as my percussion gun.

 

[M. De Land]

Next time I go to the range ,I think I'll try leaving a soft touch hole wire in the touch hole and load the fouled gun to see how many shots I can get. Hummmm? Never thought of that.........

I do it so as to leave a hole in the compressed powder column to let the flash be exposed to more of the charge along with keeping the vent clear. It's also a good safety measure by plugging the vent and not fanning a hot ember when pushing a fresh load down. It is a negative if you dry ball and bend the wire down but as long as it is soft iron or copper it can be retrieved with pliers..

 

[SDSmlf]

The vent is about .200 above the breech face surface.

I don’t have enough data from others experiencing this problem but I’m wondering if this happens when the touchhole is more than .100 in front of the breechplug. Darn liners.

Not arguing, just stating some observations. Put together a TOW 62 caliber Jaeger a while back. For whatever reason, placed center of touchhole a little over .150” in front of breech face. My reasoning was to allow for a 5/16” diameter liner installation without compromising the breech threads or face, even though I ultimately installed a 1/4-28 liner. Wanted room to step up a diameter if necessary, though I had no ‘real’ reason. Guess it’s worth noting that I added a generous chamfer on the powder side of the liner. Used a #2 center drill I believe. Touchhole ended up at 5/64” diameter from the center drill.

Fast forwarding a bit, used the gun for a youth day at a club I belonged to. Over 60 youths shot the gun at least once. Some parents also shot the gun. 30 grains of 3F was ‘standard’ load to kill a clay pigeon at 25 yards, although by request, some of the older youths and adults fired loads at 60, 90 and 120 grains. I kept the gun wiped down and the pan relatively clean. Used a looser than normal ‘wet’ patched roundball. Did not do anything with the bore, though I was ready. Refreshed the first flint a few times before changing to a second flint, which I also refreshed, though I wasn’t on a shot count, just based refreshing and change on what looked good. Didn’t have a single hang or misfire. I was surprised to say the least. Well over 100 shots total without issue.

This particular gun has moved on because of a ridiculous offer I couldn’t refuse, though I am building a replacement. Expect similar if not better performance, though not sure how I will measure.

@M. De Land, looking forward to hear what you ultimately discover to be your issue after 25 rounds. Sounds like something that could jump up and unexpectedly bite any one of us.

 

[Robby]

So I working away on my latest rifle, a .36, with a nasty little dish in the breech plug face, when the subject of this discussion popped in my head. Well, I have a few guns right handy so I grab a .58 rifle, the barrel held in with a hook breech and wedges. quicker than I can type this, I have it apart and the breech plug pulled.

This gun is around ten years old and hasn't been fired in probably a year. There is no indication of rust anywhere on the plug, the touch hole liner is bright and shiny, there is absolutely no indication of fouling migrating down the threads. If fact, it looks like the day it was originally assembled. But then fact and supposition are usually two differing things.
Oh yeah, I use a monkey wrench, about ten years older than me, to remove the breech plug, but not to worry, its left handed, always use a left handed monkey wrench to undo a right hand thread.

Robby

 

[M. De Land]

So I working away on my latest rifle, a .36, with a nasty little dish in the breech plug face, when the subject of this discussion popped in my head. Well, I have a few guns right handy so I grab a .58 rifle, the barrel held in with a hook breech and wedges. quicker than I can type this, I have it apart and the breech plug pulled.
View attachment 129729
This gun is around ten years old and hasn't been fired in probably a year. There is no indication of rust anywhere on the plug, the touch hole liner is bright and shiny, there is absolutely no indication of fouling migrating down the threads. If fact, it looks like the day it was originally assembled. But then fact and supposition are usually two differing things.
Oh yeah, I use a monkey wrench, about ten years older than me, to remove the breech plug, but not to worry, its left handed, always use a left handed monkey wrench to undo a right hand thread.

Robby

I can see fouling residue in the threads in the picture under the dip which means they are not sealed off at the front end.

 

[DuncNZ]

When I was serious about competition shooting I used a damp patch on the jag as I rammed the ball down the barrel , I use a slightly under size jag which bunches the cloth on the way out and pulls the crud with it , No it didn't pull the ball off the powder , or cause the breach to foul so much the rifle would not fire , and it certainly did not hurt the accuracy . and it wiped excess patch lube off the bore , conditioning the bore to exactly the same amount of fouling for each shot .

 

[Robby]

I can see fouling residue in the threads in the picture under the dip which means they are not sealed off at the front end.

Well, even with my Optivisor and Streamlight 800 lumen flashlight, I can say without any doubt that you are not seeing fouling residue. Perhaps you are seeing the coating I put on the threads before securing, which is a mixture of graphite and Vaseline. But then, you believe what you want to believe, there is comfort there.
Robby

 

[Ray-Vigo]

The question is how much you can shoot before the fouling becomes an ignition issue. I would perhaps modify with a recess in the breech face if your ignition is going downhill due to fouling after just a shot or two. On the other hand, if you can get 10-12 or more shots before it becomes a problem, I view it as something to clean and live with rather than pull apart and start fooling with the breech. I'm sure a gun builder would more readily resort to the modification because they have these things apart all the time.

I have a .36 cal flintlock that will build breech fouling until ignition goes spotty because it gets up to the touch hole. The small bores, I have found, tend to develop fouling issues faster than the large ones as a general thing. Having shot the .36 enough to know it will be a problem, I bore scrape and wipe once the fouling begins to become a problem. I would say this is every 10-12 shots. I look at it as a quirk of the rifle and try to remember that I have an extra step every so often compared to my others.

 

[M. De Land]

I can see fouling in the threads in the picture under the dip which means they are not sealed off.

Well, even with my Optivisor and Streamlight 800 lumen flashlight, I can say without any doubt that you are not seeing fouling residue. Perhaps you are seeing the coating I put on the threads before securing, which is a mixture of graphite and Vaseline. But then, you believe what you want to believe, there is comfort there.
Robby

Huh, odd the dark coloration is only in the threads under the breech face cut out . I cut and thread barrels on my lathe and install breech plugs personally so am speaking from experience not speculation. Think of a hydraulic hose fitting under high pressure. The threads only serve to draw the seat fittings in the flange together to make the seal . A loose fitting high pressure hose will leak like a sieve if the threads do not draw the seat against the pressure flange and the same is true of a breech plug in a muzzle loading barrel.
I'm not saying that gas is leaking out the back of the breech plug only that fouling is being driven into the threads to some degree and this is not a very good idea for a breech plug seal .

 

[M. De Land]

The question is how much you can shoot before the fouling becomes an ignition issue. I would perhaps modify with a recess in the breech face if your ignition is going downhill due to fouling after just a shot or two. On the other hand, if you can get 10-12 or more shots before it becomes a problem, I view it as something to clean and live with rather than pull apart and start fooling with the breech. I'm sure a gun builder would more readily resort to the modification because they have these things apart all the time.

I have a .36 cal flintlock that will build breech fouling until ignition goes spotty because it gets up to the touch hole. The small bores, I have found, tend to develop fouling issues faster than the large ones as a general thing. Having shot the .36 enough to know it will be a problem, I bore scrape and wipe once the fouling begins to become a problem. I would say this is every 10-12 shots. I look at it as a quirk of the rifle and try to remember that I have an extra step every so often compared to my others.

That descibes perfectly what I'm experiencing with this .45 cal flint gun only mine doesn't show up until about shot 25.

 

[Robby]

Huh, odd the dark coloration is only in the threads under the breech face cut out . I cut and thread barrels on my lathe and install breech plugs personally so am speaking from experience not speculation. Think of a hydraulic hose fitting under high pressure. The threads only serve to draw the seat fittings in the flange together to make the seal . A loose fitting high pressure hose will leak like a sieve if the threads do not draw the seat against the pressure flange and the same is true of a breech plug in a muzzle loading barrel.
I'm not saying that gas is leaking out the back of the breech plug only that fouling is being driven into the threads to some degree and this is not a very good idea for a breech plug seal .

That coloration is present the entire length of the plug, and all the way around, the mixture I use is black, probably the camera angle makes it look that way. Again, there is absolutely no indication of fouling present, all parts are rust free and the whole area looks as it did when assembled over ten years ago, a tribute to my cleaning if I do say so, Hah! Your high pressure hose analogy may not be apples and oranges, and the plug is certainly not loose fitting, but it certainly isn't apples and apples. Let me use an apple of a different species, in another incarnation of shooting sports it is not common, but far from uncommon to experience a gas leak where two mating parts are joined for the purpose of redirecting hot gas, they seal by nothing more than the pressure from two set screws, the pressure at this junction far exceeds anything we experience in place powder shooting. If it leaks, the manufacturer recommendation is to keep shooting, it will eventually seal itself. A solution commonly accepted by people that own those type guns.
I have fit dozens of breech plugs, even on barrels that come with them "Fitted", Hah! I do it by hand with files, so I know a thing or two about what works and what doesn't.
Robby

 

[M. De Land]

That coloration is present the entire length of the plug, and all the way around, the mixture I use is black, probably the camera angle makes it look that way. Again, there is absolutely no indication of fouling present, all parts are rust free and the whole area looks as it did when assembled over ten years ago, a tribute to my cleaning if I do say so, Hah! Your high pressure hose analogy may not be apples and oranges, and the plug is certainly not loose fitting, but it certainly isn't apples and apples. Let me use an apple of a different species, in another incarnation of shooting sports it is not common, but far from uncommon to experience a gas leak where two mating parts are joined for the purpose of redirecting hot gas, they seal by nothing more than the pressure from two set screws, the pressure at this junction far exceeds anything we experience in place powder shooting. If it leaks, the manufacturer recommendation is to keep shooting, it will eventually seal itself. A solution commonly accepted by people that own those type guns.
I have fit dozens of breech plugs, even on barrels that come with them "Fitted", Hah! I do it by hand with files, so I know a thing or two about what works and what doesn't.
Robby

Hand filed threads say's it all !

 

[Robby]

Well, you have gone from ignorance to foolish. I'm done.
Robby