radially inward from wall 826 a plurality of orifices 830 are disposed in wall 826 between blades 828 in the embodiment that is depicted in these figures a grouping of four orifices 830 is disposed at ninety degree intervals around wall 826 between successive blades 828 see fig1 in some other embodiments the grouping contains a different number of orifices 830 e g 7 etc and in some additional embodiments the groupings are disposed at different axial locations than is shown in fig8 and 9 as in the previous embodiments turbine 818 is brought up to speed before gun 100 is fired upon receiving a command to fire gun 100 fire control system 110 sends a signal to motor controller 115 to energize motor 116 see fig1 b the motor spins the turbine 818 up to a desired angular velocity before round 112 is fired rupture disk 224 is used to keep barrel 102 dry before the first firing the spinning turbine draws water in through orifice 832 and expels all such water through orifices 830 when round 112 is fired the round and or pressure from the combustion gases that are generated when the round 39 s propellant charge is ignited causes rupture disk 224 at the muzzle of barrel 102 to rupture turbine 818 continues to spin after the first round is fired so that barrel 102 is kept free of water after rupture disk 224 has ruptured additional rounds can be fired through the water free barrel as long as turbine 818 is spinning it is to be understood that the disclosure teaches just one example of the illustrative embodiment and that many variations of the invention can easily be devised.