I need some help! I have a Cabela's 50cal flintlock Hawken rifle made by InvestArms and I want to convert it to percussion. My problem is the touch hole liner didn't come out clean and I need to chase the threads in the barrel and and install a powder drum. I plan to buy the drum and drill kit from TOW but I need to know what thread size and pitch this barrel has so I can run a tap thru the threads. Any ideas based on experience?