is this a trick picture?? whats the bolt come from?? thats awesome .. or maybe the chuck is really small?
I have been working on this basically to for more experience. Mainly learning what not to do (don't start with a screw on oring/spring retainer). I will eventually go through the QB78 valve mods. Next being fixed oring, rear spring on poppet if that is possible.I made my own 7/8 x .065 1020 DOM tube, pinned it (should be 1.5 center screw head calculation), tested it to 8000 PSI, changed the valve around, added side cocking (spring guide screw still goes out the back). It is the same 17" barrel with a 3/4 x .083, 5/8-24 threaded extension to protect the nipple (live and learn) and bling on the front of the barrel (a beauty ring).I was getting close to 900 fps with 44.75 gr (undersized) airgun pellets so I cut the forward section off some 200 gr hard cast lead bullets I had available. They are about 100 gr and rifling engraves them (finally something .308!).I haven't done a whole lot of testing because I don't have access to a real range (saving bullets for inaccuracy testing) and I burried a 100 gr bullet in the wall behind my downstairs "trap". I have since reinforced it with rubber mulch!The string looks promising for a coyote gun but will this speed allow me to shoot accurately (stabilize but not overly stable)? I don't know but my inkling is I need a littlle more power/bullet length.2500 PSI start606 fps667 fps (97 FPE)653 fps? Ending psi (didn't have time, was ok with these).I have the 17" PB barrel (30-06 so 1:10 twist) right now on it. So my question is, what .308 airgun bullets should I be looking at for estimated stable flight. Hunters supply has 79 gr and 111 gr. I know Accurate molds has a lot of choices and NSA has some. Or maybe 1:10 is a lost cause? It is fun though.
looking good.. what size poppet are you using ?