I had somebody contact me this morning to ask how to build a .30 cal Springer.... I have never seen a complete analysis of springer designs, but my gut reaction was to tell him to make the swept volume proportional to the FPE level he wanted.... I just had a quick look at a few volumes for some common springers, and if you take the volume in cc's and divide by 3, you get the following numbers.... Individual guns may be a bit higher, but the numbers look pretty close to me....Crosman Quest / Gamo CFX/Whisper - 49cc / 3 = 16.3 FPEWeihrauch HW95 - 45 cc /3 = 15 FPEWeirauch HW80 / Beeman R1 - 57 cc / 3 = 19 FPEDiana 350 - 71 cc / 3 = 23.7 FPEHatsan 125 - 80 cc / 3 = 26.7 FPEWebley Patriot - 81 cc / 3 = 27 FPEHatsan 135 - 87 cc / 3= 29 FPESo for a .30 cal, if you want 700 fps with the JSB 44.8 gr. pellets that is 48.7 FPE x 3 = 146 cc of swept volume should be about right.... To get 850 fps (72 FPE) make that 216 cc.... Bob
Sometimes just because you can build it isn't enough reason to actually do it.
You might be focused on the mini Gas Pistons. N-Forcer does have bigger with 300 mm stroke up to 7.5 tons behind them
So lets say we use a mechanical device to cock and it's NOT a carry Gun.It would be a solid mount construction. Say the back of a Jeep or something.We have 300mm of stroke.The piston only needs to be so big right?