Hello everybody. I "started" building a flintlock over 10 years ago, and didn't make much progress. Finally back at it, and the breechplug install has got me scratching my head. Most tutorials and pictures I can find on this subject, have a much larger sealing area to deal with.
I'm wondering how it'l even be possible to get a good seal, when there's so little size difference between the plug threads, and the bore. At least by hand.
Specs first.
This is a Green Mountain 15/16 - 54 caliber barrel.
Best I can measure with calipers, the bore diameter is .535", and the groove depth is .010 (groove diameter of .555).
Barrel is tapped 5/8-18 UNF.
Here's the best real world picture I could get. Need 3 hands to get something clearer. There's some prussian blue in there, I was checking to see what the breechplug would do. As it stands, the tip of the plug doesn't contact the sealing surface, even though the plug depth is longer than the barrel hole is deep.
I believe the threads in the barrel end before the rifling starts. Drew things up in CAD since it's a good way for me to wrap my head around how things work. The distance between the end of the threads and the start of the rifling is exaggerated.
So, I believe, that in addition to getting the tang to match up with the correct flat (opposite the Green Mountain stamp on the barrel), and getting the plug tip to bottom out and seal, I will need to carefully remove threads from the end of the plug so it'l even screw in far enough.
Is that how you guys would tackle this? Or would it be better to thread the barrel a little deeper? Wondering if I shouldn't just send this off to someone with a lathe.
Thanks!