I purchased a New Green Mountain barrel from a local sport shop it is 50 cal brand new never been fired. but it is for a flint lock, can I remove the breech plug and replace it with one for a percussion it is the 15/16 octagon barrel. what process will it take for me to do this and what do I need to order. thanks, Steve

you kind of lost me here... you want to take the breech plug out? That is not going to make a flintlock into a percussion cap lock. Your best bet would be to sell or trade that one with someone for the kind of rifle you need. What kind of rifle are you going to mount this barrel into?

cayugad, the box says replacement barrel TC Hawken flint it has the screw-in breech it has the hooked breech I want to replace it with the percussion hooked breech I believe the Green Mountain threads are 5/8"-18. Thanks Steve

Is the flash hole in the breech plug, and not in the barrel???

Yes it is in the breech plug.

I would call GM and ask it they will swap it out.

The T/C Hawkins flintlock barrel,to change over to a percussion I do not think has anything to do with the breech plug. The difference is in the ignition system. Instead of a touch hole that the flintlock has, it needs a bolster with a nipple port. What twist barrel is it? It might be easier to sell the flintlock barrel and then purchase a new persussion barrel.

If the flash hole is in the breech plug, I am lost on this one. Can you post a picture of the end of the barrel with the touch hole in it?

I see what he is doing/thinking.
Remove the flintlock breach plug and install a percussion breach plug.

Sorry I don't have the information you need though.

Al