I picked up a never used tanged percussion breech plug a while back 1" 5/8"x18 2 1/2" tang and the "Offshore" chamber is right at .265". Been sitting on my desk for a while periodically taunting me as to the direction it goes. Other night I remove finger tight nipple and look into holes with flashlight and flame hole is about 85% blocked under nipple, hummmm? Looked at it really well with magnification and you can see the circle location through flushing on side surface on exterior of a pin or screw covering flame hole drill. Not being able to see any threads on internal protrusion my head starts leaning to machine tools in garage.
Questions- Would you drill/clean out whatever and tap for a set screw custom fitted correctly timed angled tip to create a now you know for sure? Also would you open up the Offshore chamber some for maybe a better everything.
Thanks, Lar---