I am in the process of repairing my baby "Cyrano 55" as it popped its power regulator control shaft "O" ring after not having been used for about 5 years. I think the "O" has stuck on the 4 mm OD control shaft without being moved and being under full air pressure for all of that time, plus the gun does not seem to have much oil in it. Always held air and never leaked anywhere before until I recently moved the power regulator cursor to check it out, so I do not know where the rest of the oil went, but maybe it was never inside there in the first place. The oil certainly did not exit via the cursor control gate in the handle as it only leaked air when I pushed the cursor forwards and stopped as soon as I let it move back.
It occurs to me as I look at the disassembled muzzle assembly that there is another way to convert a "Cyrano" gun (and others) to pneumo-vacuum operation. Most conversion kits work on the muzzle nose end piece to create the inner barrel vacuum sealing system, but in the "Cyrano" and other guns with a removable muzzle nose end piece it should be possible to create the sealing system around the shock absorber body. What is required is an "O" ring in the thick rear plastic flange of the shock absorber body (it would require a groove machined there to take it) or one located at the back of the rubber sleeve against the step of the flange with the sleeve shortened to make space for the "O" ring which will seal the outer periphery of the shock absorber body in the smooth bore it slides into in the muzzle body and around the exterior of the shock absorber body itself. It needs to be a dynamic seal as the shock absorber body moves when it gets hit by the piston.
The shaft sealing "O" ring has to mount in the front end of the shock absorber body, which needs something to keep it there and maybe requires a new shock absorber body design at the front end. Now if you pick up a Mares big port muzzle and give it a shake you can hear a slight rattle as the shock absorber is not always tightly gripped, plus there is extra space between the front end of the delrin shock absorber body and the interior of the muzzle nose end piece which has a conical end well when looking inside it from the rear. This gap could be used to mount a rubber washer that controls an inner shaft sealing "O" ring located directly behind it, hence the new washer would not be a seal itself, but would restrict the "O" ring from moving off axis. There is more length in that well at the front than is required for the forward movement of the shock absorber under piston impact (but I don't know how much more), so some of the space could be used for fitting another component, especially a soft one. More rubber in there would add to the shock absorbing capability of the muzzle as right now any shock is taken by the flange at the rear end of the shock absorber body acting on the surrounding rubber sleeve. This system should work for shafts without a tail end stop diameter and if the "O" ring could be given some freedom to momentarily expand and let a shaft tail stop diameter through then it might work with them also. I see the benefit of this system is a shorter muzzle for pneumo-vacuum operation, in fact it will be the same length as for a wet barrel gun. Unscrew the muzzle nose and replace the shock absorber with the standard one and you could go back to wet barrel operation.
As Tromic has done the existing muzzle relief port holes would need to be covered with a rubber hose to seal them off. The screw in muzzle nose end piece would not need to be sealed on its screw threads as the necessary sealing would all be carried out on the shock absorber body located behind it. Something to think about anyway.
It occurs to me as I look at the disassembled muzzle assembly that there is another way to convert a "Cyrano" gun (and others) to pneumo-vacuum operation. Most conversion kits work on the muzzle nose end piece to create the inner barrel vacuum sealing system, but in the "Cyrano" and other guns with a removable muzzle nose end piece it should be possible to create the sealing system around the shock absorber body. What is required is an "O" ring in the thick rear plastic flange of the shock absorber body (it would require a groove machined there to take it) or one located at the back of the rubber sleeve against the step of the flange with the sleeve shortened to make space for the "O" ring which will seal the outer periphery of the shock absorber body in the smooth bore it slides into in the muzzle body and around the exterior of the shock absorber body itself. It needs to be a dynamic seal as the shock absorber body moves when it gets hit by the piston.
The shaft sealing "O" ring has to mount in the front end of the shock absorber body, which needs something to keep it there and maybe requires a new shock absorber body design at the front end. Now if you pick up a Mares big port muzzle and give it a shake you can hear a slight rattle as the shock absorber is not always tightly gripped, plus there is extra space between the front end of the delrin shock absorber body and the interior of the muzzle nose end piece which has a conical end well when looking inside it from the rear. This gap could be used to mount a rubber washer that controls an inner shaft sealing "O" ring located directly behind it, hence the new washer would not be a seal itself, but would restrict the "O" ring from moving off axis. There is more length in that well at the front than is required for the forward movement of the shock absorber under piston impact (but I don't know how much more), so some of the space could be used for fitting another component, especially a soft one. More rubber in there would add to the shock absorbing capability of the muzzle as right now any shock is taken by the flange at the rear end of the shock absorber body acting on the surrounding rubber sleeve. This system should work for shafts without a tail end stop diameter and if the "O" ring could be given some freedom to momentarily expand and let a shaft tail stop diameter through then it might work with them also. I see the benefit of this system is a shorter muzzle for pneumo-vacuum operation, in fact it will be the same length as for a wet barrel gun. Unscrew the muzzle nose and replace the shock absorber with the standard one and you could go back to wet barrel operation.
As Tromic has done the existing muzzle relief port holes would need to be covered with a rubber hose to seal them off. The screw in muzzle nose end piece would not need to be sealed on its screw threads as the necessary sealing would all be carried out on the shock absorber body located behind it. Something to think about anyway.