I picked up short strand body filler, yes bondo.
After reading that it will take more time to cure & then must be sealed, I’m beginning to believe epoxy might be better.
I’m going to look for poly resin now. Rifle didn’t arrive today anyway.
Due to cure time I’m starting to think an epoxy would be a better choice than the glass filler. I plan to get the rifle from my LGS today when it comes in & make the call.