It is probably down to the latter but I’ve already managed to prang the handle of that sledgehammer I mentioned the other day. I probably should have concentrated more on aiming than on slamming the hammer down as hard as possible. I think I caught the hammer with the handle rather than the head and that was it.
So, time to learn the skill of replacing a handle. Meanwhile, in better news, I did at least prove that the splitting grenade works well with longer logs and even a club hammer is enough to get the wood to crack open. In future, more accuracy and less brute force, I think.