3# is typical for a SXS game gun and 3 1/2# fairly typical for a pigeon gun. At 4# 9oz, I'm going to guess a big bore long range fowler. Barrel weight and weight distribution must be matched to action + stock weight and weight distribution to achieve ususal balance range and usual swing efforts. If you were to "shoehorn" a set of long, heavy barrels on a light stocked action you would find the balance so far forward as to compromise handling, most likely.