An Unusual Patent Breech

[TNVolunteerEngineer]

I acquired this set of parts at an estate sale. There were extensive ML items. This breech is bored all the way through and threaded two different threads front and back. The barrel threads are larger and abut a shoulder between them and the breech plug/tang threads. Is this a copy of an old concept or a new idea?  There is one finished breech with a serial number and two identical partially completed castings.  The plug on the barrel side is threaded like the breech end of a barrel.

Here are some photos:

[Robin Henderson]

Looks like the same breech as my P58 Enfield rifled musket.

[Robin Henderson]

Here's a pic.
 

[Clark Badgett]

Looks like the same breech as my P58 Enfield rifled musket.

This is right. If you decide to part with one give me a heads up. I'm interested in one.

[TNVolunteerEngineer]

I have three breeches but only one tang plug. I'll sell the two extra breeches.

[L. Akers]

This would be a neat way to convert a flintlock to percussion.

[Clark Badgett]

I have three breeches but only one tang plug. I'll sell the two extra breeches.

PM sent

[Clark Badgett]

This would be a neat way to convert a flintlock to percussion.

Or to make a late trade gun