BOLT Airsoft announced that they will have a their BOLT M16A4 B.R.S.S. Heavy available to the airsofters soon... "B.R.S.S. Heavy is a new design for fixed stock models, with the new structure the recoil kicks to the shoulder stronger and more reality than B.R.S.S. models. B.R.S.S. Heavy reacts with longer fixed stock tube which brings more powerful recoil feelings for the players, and also the strongest recoil system of BOLT AIRSOFT."