what is the benefit of a fluted barrel
Fluting (firearms) The main purpose of fluting is to reduce weight, and to a lesser extent increase rigidity for a given total weight or increase surface area to make the barrels less susceptible for overheating for a given total weight. However, for a given diameter, while a fluted barrel may cool more quickly, a non-fluted barrel will be stiffer and be able to absorb a larger amount of total heat at the price of additional total weight.[1][2][3][4]
Bullpup A bullpup is a firearm with its action and magazine far behind its trigger group. This configuration permits a shorter overall weapon for a given barrel length. This maintains the advantages of a longer barrel in muzzle velocity and accuracy while improving maneuverability and reducing weight.