Well I have had a good look at the existing photos on the web-site and read all the text. Where the "Pelengas" differs from guns that we are used to seeing is in the construction details. The rear bulkhead is essentially a machined and profiled disk with an integral sleeve section of smaller diameter projecting forwards that the inner barrel fits into as a socket attachment. The inner barrel does not screw into the rear bulkhead, instead it is held in place by a transverse pin passing through them both (a similar attachment is used in the "RPB-1"). The inlet valve sits in the rear end of the inner barrel behind another transverse pin which retains its biasing coil spring and is a rubber or some other compliant material in the form of a disk that replaces a valve stem. You push a blunt pin through a small hole in the rear end to displace this disk and let air out of the gun, the disk is nipped away on the sides with crescent cutouts so that air can flow past it easier as it moves away from the flat seat in the inner rear of the bulkhead. Anyone who has a "Seabear" (or "Orion"/"RP") AK model will recognize this type of inlet valve, but there the rubber valve disk has no side cutouts (MAK models do have a metal valve stem, but in a completely different rear bulkhead that has a "power dial").
Only the front end of the inner barrel has a screw thread that the muzzle attaches to, so you assemble the rear bulkhead on the inner barrel and then push the tank over it and then add the front bulkhead which is held in place by the threaded connection to the muzzle. There appear to be two forms of muzzle, a short version in metal with 6 relief ports for a wet barrel gun and a much longer muzzle in a cylindrical form with a removable plastic nose piece that contains the actual vacuum sealing cuff for "dry" barrel operation. As you can unscrew the nose piece with the gun still under pressure the cylindrical muzzle must contain an internal diameter restriction which the damper or shock absorber sleeves (two polyurethane bushes, innermost harder, outermost soft) are pressed against by uncocked gun pressure forcing the piston onto them and another restriction which keeps the damper sleeves in the muzzle and acting from their rear. I expect that the muzzle is constructed of three pieces, a plastic nose piece or "cup", a knurled outer periphery joining section that traps the damper sleeves in the muzzle body and the cylindrical muzzle body itself that screws onto front end of the inner barrel. Alternatively the damper sleeves press in from the rear of the muzzle body which would eliminate any seals in the muzzle body at any threaded circumferential joint, in which case the metal muzzle body is one-piece, but relies on the damper sleeves being held in place by being a tight fit. To absorb an impact the damper sleeves ideally need somewhere to expand as they deform (well the softer sleeve anyway) and change their shape momentarily, but those details are unknown.
What holds the grip handle in place on the tank's cylindrical rear section and indexes it at the correct orientation I also do not know, but it has to line up with any access hole through the tank wall that the trigger transmission pin passes through that is used to tip the sear lever over to fire the gun. The parts that this small diameter transmission pin (2 mm diameter?) pass through look very similar to their counterparts in the Mares "Cyrano", but are made from non-plated brass or bronze. Rather than a biasing vertical coil spring pushing down on the rear end of the sear lever a spring is provided by a ring form spring encircling the inner barrel tube that lifts the front end of the sear lever instead.
The black with rear orange strip highlight grip handle appears to be of a larger size than usual, but the important hand span dimensions are much the same as the grip is not overly raked in terms of its angle to the longitudinal axis of the barrel.
The "Pelengas" gun costs about the same as a "Taimen" if you don't include the reel and currently is available as a "55 +" and a "45" model with longer barrel guns under development. Now all we need is someone here to buy one!
