I just did the weevil mod this afternoon to my new-to-me, NOS Caiman X. I didn't have the same problem as these Gen 1 Caiman's are known for: Instead of slowly decreasing in speed over the shot string, my gun shot real slow at first, and over 50+ shots rose almost 600 fps! Yikes - starting at 357 and slowly but surely heading up to 950 before it stabilized just for a bit and then started dropping off as the cylinder pressure dropped. So likely a very creepy reg from the start, holding the valve from fully opening until pressure in the cylinder dropped.
Since this is a NOS gun, I was wondering whether the reg might just need some time to start functioning properly. But I figured WTH, I'll see how it does when it can breathe properly. So I did the Weevil mod and things are working great now!
I set the hammer spring for about 910 fps with 25.39's (my gun is a .25 cal) and the accuracy at 25 yds where I have tested it so far is one hole. Spread over the entire shot string was a little high as 40 shots pushed the air capacity a little much (starting from only a 240b fill). But still only 26 fps with an SD of 5.1. And with that speed difference there should really be no POI change out to at least 40 yards over the entire 40 shots.
Thank you weevil for your airgun acumen, and for publishing such a great fix for the Gen 1 Caimans!
