"DrPutz"BigTinBoat - thank you for the suggestion of the hammer spring. I had upped to the next larger hammer spring when I had problems with the Viton o-rings, I will have to drop back down and test again. I need to cut a bit off the lighter spring to reduce the bounce and make some air this weekend. One thing on the 177 is the regulator (huma old school) takes up a bunch of space for extra plenum, so probably working with only 126 cc's of air.
For the breech crown, you may need more than you think. My original was about 1/16" - I upped that to about 1/8" since it would not harm anything. On my 25, the JSBs feed much easier now.
Here is a shot string from tonight from the 25 cal with Barracuda pellets - 220 to 120 bar, 1.4 fpe/ci efficiency 5% variation for 40 shots. Probably a bit too far on the number of shots, but could go to 230 bar, once I have more air. The 25 does JSB 25.4 gr (old style), Barracuda Extreme, and Barracuda Hunters all at 30fpe. The Barracuda's are the most accurate at the moment at 50 yds. I'm not sure the 25 cal is living up to the extra expense of the pellets - may have to get a 22 Bantam instead.
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