Vices and hard surfaces and anything else that keeps a HUNTING rifle from acting like it was fired from a field, shouldered position, zeroes differently and creates different muzzle reactions on firing, during what would be normal follow through. You might fire from a firm rest, or a bipod, or a shooting house window, or a tree trunk, but you’ll generally have something between your forearm and any hard surface, Not much else acts like your shoulder, either. Bags and rests and bipeds don’t interfere with that imitation. Even all sorts of improvised rests and positions don’t. Vises do. Never been able to mimic a vise. LOL