Originally Posted by
draitzer
Qualifying note: this may not apply in your case, but...Many years ago, a friend of mine tackled replacement of the leather on a bellows gun. In his case, the hollow butt was actually split longitudinally for original installation of the mechanism and glued together (the seam was barely detectable). He managed to pry that joint apart and open the back end for removal of the innards. I happened to visit his shop at the point he'd propped the thing open a couple inches, amazingly without breaking the wood.
From the photos, yours looks more complex, but it could be worthwhile to look for any place that has a seam that would allow spreading of the butt end wide enough to let the axle pass by.
Best of luck on your audacious project!
Don R.