I am agonizing over this. The rifle I am copying is the unsigned Catawba rifle by Micheal Briggs in our library. I have contacted him but he no longer owns or has access to this gun. There is no picture of the inside of the patchbox. I have been studying mechanisms for side opening PBs. But this one seems different. The release button is in the top of the butt plate.
It would be simple enough to reverse a toe plate mechanism to work in the heel extension, but there is a problem of the screw. It would seem to me that a better place for the catch would be in the top (middle) of the lid instead of the side/end near the butt plate.
In this situation, it would be fairly simple to drill a hole straight down from the location of the release button into the cavity of the patchbox, engaging the release catch, and acting as a spring for the pushrod. I'm sorry I can't post a drawing of this.
The only drawback I see with this is the mechanism would be exposed to the inside and contents of the box. In other words, something could get hung on the release or maybe a lead ball could knock into it and spill the box.
One picture of the original shows the release button pretty clearly. It seems to point forward not straight down.
Another NC gun in the library by Jackson Craft shows the inside of the patchbox. It shows the mechanism is isolated from the cavity. It also shows the release spring screwed to the bottom of the cavity. I suspect the "inlay" on the catawba gun opposite the PB is actually a captive nut holding the release spring.
So if anybody would like to help me figure this out I'd sure appreciate the input.
