The fellows at the shop are interested.
I'll be getting some materials and going forward with this.

For shotgun, bore rifle, and BPE chambers - and many NE chambers, this should be a good solution.
I don't know why I hadn't ever thought of this.
I and many other guys I know have thought of the epoxy materials, but one way or the other we've all steered clear of the plastic fantastic.

I'll post back with whatever I learn.
I will be talking to my dentist too along the way.
I'm sure he'll have some good points to consider.