yea, it is off of the ron ehlert video on building chambers kits. I don't need an exact copy I just like that it is straight, not teed like most screw driver knapping hammers
A somewhat similar tool is the Pickering Tool, said to be the first musket tool adopted by the Continental Army. Truth is, it was designed and put in the manual, but has no record of manufacture and issue. I believe Townsend's has one. There are a few sutlers who carry them.