double barrel rifle - trouble shooting help

Double fire

A question here. From you description, it would seem that the breech plugs were fitted first, then filed flush.

After that, the hole for the swivel bolt was drilled and tapped? Is the swivel bolt big enough that it would have had to be threaded into the breech plugs?

If so, the leakage around the threads would be very possible.

It would seem that the greater pressures from large charges of powder and heavier bullets are causing a flash over into the other barrel. If it were a shotgun, I would suspect a small hole between the barrels, but being a rifle, with more metal in the walls, this would be unlikely. The logical thing is a leak around the threads of the breech plugs. If you can get the pivot bolt out, you might try a bit of removeable loc-tite to seal any leaks.

It would also depend upon what was used for breech plugs. If the barrels were bought separately, then welded together, the threads for the breech plugs may not have been in them. If the breech plug threads were done with an ordinary available tap, and standard bolts were used for the plugs, there was probably a very loose fit to the plugs in the threads. I have fitted standard bolts for breech plugs this way, but have used a slightly undersized tap, and done it in the lathe to get a good alignment and a tight fit.

Since it seems to work all right with lighter loads, I would use it for targets, plinking, or light game, and keep it as an example of your father's workmanship.
 
From what you are describing, the design seems flawed as well as the poorly fitting breach plugs. I suspect there is a good chance that the female thread in the barrel is poorly done and possibly funnel shaped from allowing the tap to wobble around while starting the threading process. I suspect you need to confirm that the female thread is sharp and straight not tapered and then make new breach plugs on a lathe to accomodate what I suspect will be oversize threads. Alternately you may have to set the barrels back3/4" and retap and rebreach.
The way the pivot pin is attached sounds like it leaves relatively little "meat" between the powder charge and the next barrel.
Somewhat difficult without pictures

cheers mooncoon
 
mooncoon said:
From what you are describing, the design seems flawed
Click to expand...

maybe not the strongest design, but hard to make a swivel breech any other way. Unfortunately you need it to swivel in the centre of the barrels, and that is where you need to drill into. While not that common of a gun, that is how they were made.

Not sure if these pictures work, but hopefully I can manage to get them to show up.
fishhogfishing
 
well that is a nice red X I managed to post.
how about this.

http://s619.photobucket.com/albums/tt273/fishhogfishing/?action=view&current=132407.jpg#!oZZ1QQcurrentZZhttp%3A%2F%2Fs619.photobucket.com%2Falbums%2Ftt273%2Ffishhogfishing%2F%3Faction%3Dview%26current%3DIMG00093.jpg%26

If you go to this link, you should be able to scroll through the pic's.
1st one is a close up of the breech. I cut a slot in the breech plugs with a dremel and tried an impact driver to get them to budge with no luck. So what your seeing is both barrels, the swivel hole drilled in the middle. The small holes are the stops for a spring loaded ball bearing which lets the barrels swivel into the right postion. You will also see the pan and frizzen (one on each side.) The rest of the lock stays with the stock when you remove the barrels.

http://s619.photobucket.com/albums/tt273/fishhogfishing/?action=view&current=132407.jpg#!oZZ1QQcurrentZZhttp%3A%2F%2Fs619.photobucket.com%2Falbums%2Ftt273%2Ffishhogfishing%2F%3Faction%3Dview%26current%3DIMG00093.jpg%26
 
There are other ways of making swivel breech rifles that do not require drilling into the barrels like that. The barrels can be fitted to an intermediate plate, which has the axle. The original I had was made that way, and the barrels hooked into the plate - the same way that many barrels hook into a standing breech..
Anyway, you have a gun with leaking breechplugs that are not readily removable.
You could try drilling a pair of holes into each plug, and using a two pin spanner wrench.
I have a feeling that the best fix in the long term would to be to rebuild the gun.
 
FishHog said:
maybe not the strongest design, but hard to make a swivel breech any other way.
Click to expand...

I am not sure that you recognize where the flaw is --- the flaw is (from what I can see) that unless the breach plugs are several threads beyond the end of the pivot bolt, hot gasses will leak from one barrel to the other. With extended shooting of heavy charges, you will additionally get gas cutting and almost direct channel from one barrel to the other so that it will fire both even with light charges.
The flaw is not that it has a pivot bolt in the center, it is that the breach plugs are not screwed in far enough to seal the barrels from the threaded hole for the pivot bolt.
Were the gun mine, I would remove the existing plugs with an easy out then drill and thread the barrels for at least 4 threads beyond the end of the pivot bolt and when installing the new plugs, I would seal the threads with loktite. I would also make breach plugs with recessed breaches so that the existing vent location would not change.
There is little doubt in my mind that you are getting flame leaking from one barrel to the other and that there is probably only one thread or so separating either barrel from the center threaded hole for the pivot bolt
It also seems extremely unlikely that you are getting flashover from one pan to the other.

cheers mooncoon
 
understand and thanks for the clarification and assistance. I checked that last night, it appears the breech plugs have recessed breaches. Approximately 1/2" beyond the vent hole, so they are a ways past the pivot bolt.

That being said, they are still leaking, so it doesn't much matter. I think I will try the EZout and hope for the best. I've never had great luck with them, but hopefully I can get these breech plugs out and start over. It worked well for a lot of years, perhaps I overstressed it with heavier loads, but if I can get it back to the way it was, at least I'll have a shootable gun. Not quite ready to hang it up on the wall. I guess what I'm going to try isn't going to hurt the appearance, even if I fail.

thanks for the help.

FishHog
 
roughly speaking, most muzzle loaders have about 5/8" of tightly fitted threads between the "chamber" and the outside at the back. Yours should have a similar amount past the end of the pivot screw hole. If yours already has that much thread beyond the hole then there is something grievously wrong with the threads but my guess is that there is less thread than you think. Hopefully if WD 40 leaks through, it also means that the threads are loose enough to remove without an excessive amount of difficulty.

cheers mooncoon
 
My main thought having read this thread is that's a very big load you're shooting. After much experimentation and many hundreds of rounds I shoot 55 gr 3F with a 445 ball and 010 or 015 patch out of my 45 flint longrifle. I only use roundballs - that's what longrifles were designed for and only roundballs were used in them originally. A well-patched tightly-fitting roundball can be highly accurate and deadly. I found that much over about 60 gr, certainly over 70, a significant part of the powder load was being burned outside the barrel - impressive jet of flame but basically wastage.

Beautiful looking rifle - very nicely made.
 
Be careful with those charges and the conical, you're likely developing double the intended pressure for that gun. It's a beautiful gun, by the way, your dad had fine taste. Fitting new plugs won't be too difficult, check out trackofthewolf.com for everything you'll need. I'd be concerned about the barrels' threads now, with those massive loads under a conical, and gas leekage, they make be rather weak and potentially gas cut.
 
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