I suspect the firing pin needs to come out and the interior cleaned. It's the only thing left to check out. The shotgun shell gets a faint dint from the pin not going far enough forward. It's not the wood pressing against the leaf spring so.....what's used to unscrew the cylinder that surrounds the pin ? Do I make a tool ? The bottom barrel fires fine. The piece has a new 100 % hand inletted stock made from scratch. What a job !!!!!

You're looking for a spanner wrench. You could make one or buy an adjustable one ,some of those having interchangeable pins. Google 'spanner wrench 'and see what you need .For one gun it's probably easier to make one if you have the tools -drill press ,drill rod ,etc.

Straight or angled circlip pliers usually do the job admirably.

I replied over on th eother forum where you posted, but I think another option is Wisner's Inc. He makes springs and some other parts for the Miroku's, You might call him.

I still think your buddy is over his head. I have made special spanner wrences for many different sizes.

Much thanks guys. I'll get the shotgun working thanks to you folks. I think I also bought a special 'wisner bolt shroud peep sight some time back". Beautiful machining.

Again thanks to all of you.