SSG-Kinda disappointed.

Well, My Dad wanted to turn his Mrod Gen.2 .25cal up to shoot around 880-900fps. I originally tuned it around 830-850fps to get 30 shots out of it. So, I thought I would try the SSg(not listing Brand name) try to get the target fps of 880-900 and still get good shot count. But, I was wrong. I was unable to reach my goal. To get a small curve out of it I could only get 830-850fps out of it. Didn’t gain anything! So, I shimmed the SSg spring got it turned up all the way It will start out at 900fps and go down to 866 for 16 shots. Fill to 3100psi, refill at 2400psi. Personally not worth the money. Unless I’m missing something. I think it would work great for .22 or .177cal.