The question of interchanging parts is mixed. The stock needed much work from my Dremel to fit the trigger group/spring, the trigger guard/screws different lengths, and the tang reinforcing plates were not the same length. From the exterior you would be hard pressed to see any but one issue. It is the Chassepot's tang being much narrower than the Gras' and when viewed from above you can see a clear gap between the tang and the stock. That said, I am pleased with the surgery and total cost was about $90. When added to the $250 for the sporterized Chassepot, I am happy. Also replaced the rubber bolt gasket and firing needle with about $5 in parts. Randy