O rings... Not something I've really paid much attention to before, but if you size them right then there's performance to be had.
Im putting my AK back together (new piston... Don't ask!) and it occurred to me that although the O ring that was on it gave a good seal, it seemed a bit tight. So I went through the tub'o'gub and found a few to try. And the one that gave the best results? That would be the one that had no resistance when you push the piston down the cylinder, but still seals when the piston is moved sharply. It has a poor seal if you simply block the nozzle and push the piston, but give it a jolt so the O ring can seal against the head and the cylinder due to the piston head ports... Winner!
Except now I've got to take it apart again and remove the guide bearing to try and get the fps back down under 350.
Im putting my AK back together (new piston... Don't ask!) and it occurred to me that although the O ring that was on it gave a good seal, it seemed a bit tight. So I went through the tub'o'gub and found a few to try. And the one that gave the best results? That would be the one that had no resistance when you push the piston down the cylinder, but still seals when the piston is moved sharply. It has a poor seal if you simply block the nozzle and push the piston, but give it a jolt so the O ring can seal against the head and the cylinder due to the piston head ports... Winner!
Except now I've got to take it apart again and remove the guide bearing to try and get the fps back down under 350.