Hi Richard.
The gun has both front and rear sights. So the gun was designed to be AIMED, not just pointed as is the case with a front sight only. What's interesting, is if I bring the butt stock up to the cup of my shoulder in the normal manner, it's easy to aim. But muzzle heavy due to the long barrel. (This was easier to do 40 years ago LOL). But, if I cup the butt stock under my arm pit, it's also easy to aim, and steadys the barrel easier. So it would be easy to aim either way. Which makes me wonder if they were designed this way? Interesting.
Breech Area: The bore inside the muzzle end measures about .59 caliber (about 15mm). The OUTSIDE of the rear of the breech area measures 1 9/16" (about 39.69mm). I used a piece of wire and put it through the vent hole at the breech. And the INSIDE of the breech area measures about 1 3/16" (about 30.16mm). The breech plug ends just behind the vent hole, which would be normal. And the plug seems to be about 1/2" (about 12.7mm) deep into the breech area.
So what this tells me, is that the breech area is definately LARGER than the bore diameter. My best guess at the moment, is that the inside of the breech area is tapered, or some what cone shaped, and tapers smaller as it meets the standard bore diameter. Hmmmm. The only way to know for sure is to drill out the plug material. Which I will do. I plan on taking the barrel off this afternoon. I'll take good pics of the breech before sending it off to the gunsmith.
If the breech area is, as I suspect, cone shaped, this will present some potential ballistic and cleaning issues I won't cover at the moment. Just have to wait and see wnat the interior looks like. Wish me luck. LOL
Rick.