converting modern SxS barrels to PC?

[petew]

Has anyone converted modern SXS barrels to percussion caps? The barrels on my 20 double are pretty bad and I an going to use a set of modern barrels to make the old shotgun shoot again.
I removed all the lugs on the bottom of the new barrels and started fitting them to the stock . They will need a bit of wood dressed to make them fit proper . The first problem is the breech plugs. I can not find new ones anywhere . It is looking like I will be making plugs from scratch. This brings a problem, as the chamber side walls are only .165 thick now. This doesn't leave much room for taping a 3/4 x 16 thread and making a shoulder to seal against at the front of the plug.

If someone has attempted this can you share how you addressed the plugs ? size you used? thread? etc and if you were able to purchase plugs or had to build them from stock.
Pete

 

[mooncoon]

I haven't done it myself but my impression is that the plugs used a long threaded portion in order to reduce the diameter of the original chamber. It sounds like you have a metal lathe and you might consider using a double thread in stead of a single one. Basically 2 parallel threads and they only need to be half as deep. You can make a matching tap out of something like 4140 and after hardening, use a Dremel tool with a cutting disc to cut chip channels in the tap

cheers mooncoon

 

[tiriaq]

If you can get hold of a copy of Brockway's book on building muzzleloading double shotguns, there is a lot of information about breeching up modern barrels for muzzleloader use.
As mooncoon stated, it is necessary to make long plugs that fill what is left of the chambers. They should be turned to fit the forcing cones. They are drilled out to create owder chambers. The powder must fill the chamber, so that there is not an air space when loaded.
You mention wall thickness over the chambers. What is the external diameter?