stick a tape adhered wheel weight on the barrels near the muzzles on the bottom. It doesn't take much near the muzzles and it really changes the dynamics of the gun. If it fixes your problem with "too lite", you can make or have made a conformal weight, out of steel, that fills the shape between the barrels on the bottom rib. This can be blued and attached with something more permanent like clear silcone to make it all but undetectable.