Quote Originally Posted by nak81783 View Post
Now we still need from center of rear field strip screw hole to start of breech slot on the main body piece for both markers, please. That should complete the puzzle.
Actually, I guess I didn't need this. Since both the feed tubes start at the same point from the aft edge of the breech piece, I think we're back to the 3 machining options I mentioned before.

Did anyone see if velocity increases by plugging the feed tube threading?