A minimum charge almost always backs out primers for me. I thinkall you need to do is step up the charge weight and the primer drama will go away. Accuracy doesn't look too bad at pistol distance, so stretch it out a bit!

You are correct as regards the bore. Lots of conflicting info out there! As you have measured, the bore is original, just the lead is longer. Which doesn't help accuracy, but doesn't destroy it for military purposes..