I have epoxy bedded many wood, laminated, & plastic stocks during the past 50 years. I remember when the Brownell's Accraglass (sp?) came with a packet of powder that might have been asbestos to make it less runny.
Last winter wifey bought a big cast iron pot for stew making in the oven at temps of 350* plus. The precious, high price, pink pot suffered a chipped handle that if left unrepaired would have promoted further deterioration of the delicate, pink enamel coating and presented a rough sharp surface to compromise grasping using oven mitts or pot holders. I was detailed to remedy the situation and, in the process, I selected J-B Steel as a way to restore the item to functional use. Lots of stews at 350* and the J-B Weld Steel still sticking, tight, hard & smooth. The dark gray J-B presents somewhat of a color discontinuity with the pot's soft muted pink color.
The next logical step was to buy several packets of the J-B Weld Steel epoxy for under $6 each for rifle bedding. Kiwi works good for release agent & filling recesses. One pack of J-B steel good for one bedding job. Made nice handles for wood rasps and fixed an awl handle with the excess after the bedding job. I'm not fussy about the dark gray J-B steel color, makes sort of a nice boundry outline. Not excessively runny & ample working time. Glued some fore-end tips onto stocks using J-B steel that flowed into hole drilled into tip & stock joint for strength and clamped together with surgical tubing until set. No shrinkage. Strong hard surface for recoil lugs. "Strength 5020 PSI" Don't have any anti- aircraft artillery so can't comment on extreme compressive recoil force aspects.
Edit: Making J-B Weld Steel in a variety of colors might be difficult but addition of various inorganic compounds containing cadmium, iron, zinc, & others might change the utilitarian dark gray color & provide nicer tones of walnut or certain shades of delicate pink. When toasted at temps exceeding 350* the colors would remain unchanged and remain attractive as part of the non-shrinking, temperature resistant, high strength, surface degradation resistant (like stays smooth) J-B Weld Steel.