Webley Patriot Gas Ram Tune
I recently picked up a new Webley Patriot .22 with with the intent of of gas converting it to a gas ram. I ordered the correct sized 75kg gas ram and disassembled the rifle. In side the rifle was full of grease, this was causing dieseling a full clean out was in order. The cocking slot was de burred and the piston polished. The OEM piston seal was under sized 29.80mm on a 30.05 cylinder. I fitted a new piston seal and then carefully installed the piston into the cylinder without damaging the seal.
The barrel breech face was only partly machined form the Hatsan factory, so off to the mill. With the breech face flat and square the breech seal was fitted.
Another issue I have is with the excessively large transfer port at 4mm I feel that it is to large for .22 probably ok for .25 cal. And I know from gas ram converting the Hatsan 125 that the piston will be hitting the end of the compression tube. Reducing the port size to 3.5mm will hopefully slow the exiting air and cushion action of the piston as it nears the end of its travel. I will machine a tight fitting brass insert and glue it in place with loctite super glue. This is removable and not permanent, the insert area can be heated and the insert pushed out if required. The brass insert was machined to OD 4.13mm ID 3.5mm and length 5mm.
Now that the insert is in and the breech face machined the barrel can now be fitted. The barrel fitted a lot better now that the breech is flat. Before the pivot screw was hard to install and the torque required was damaging the head of the pivot screw.
Now to the next issue. The recoil dampening system has a nylon bushing where the front stock screw goes through. The OEM bush is useless and drastically under sized on the ID. A new one will have to be made from Delrin OD 12.12mm ID 7mm length 23.20mm.
The rifle was now fully reassembled and test fired. The metallic ringing noise at the end if the firing stroke has lessened. The pivot bolt is easier to install and the barrel easier to move, also the front stock bolt now fits better.
initial chronograph testing yielded 1012 fps with RWS Super Dome pellets 14.5 grains in weight. 32 ftlbs not a bad start with a new seal things will settle down over the next 100 shots and then I can do a full test with reliable results.