... K-sqrd is saying a spring gun uses 3,318 psi to get 17 fpe . If that were true the pcp would use its full tank of air on 1 shot just to get the pellet to 17 fpe . Which you can see is not the case at all . To get a pellet to have 16fpe you only need to use 163 psi behind the pellet so why would you think you need 3,318 psi to produce 17 fpe ? 163 psi is whats pushing the pellet out of the barrel at around 900 fps . ...
Thank You, nced for your posting. I’ve often wondered and and have done several searches over the years to see if any one has done a comparison between the Cardew test and an air gun using a more modern seal. I could never find any definitive info, just anecdotalresults of before and after tunes along with lots of opinions. Makes you wonder about the wisdom of scoring the compression tube.
If you pump the pcp gun thats in the video above up to 163 psi and stop it will send a pellet out of the barrel at 900 fps . It will only fire one time because the tank will be empty . 900 fps is 900 fps no matter if its comes out of a spring gun or a pcp. The pressure behind the pellet as it leaving the barrel is going to be the same amount of pressure if the same weight pellets chronys at 900 fps . If you chrony the lets say 10 grain pellet from a spring gun and it reads 900 fps and then you shoot a pcp charged up to 163 psi and the chrony reads 900 fps with the same pellet weight that means the the spring gun is sending the pellet out of the barrel with the same exact amount of psi as the pcp . If the psi was higher in the barrel the pellet would come out faster . If the pellet was coming out slower it would be less psi . So since we can measure on a gauge how much pressure is in the pcp ans we know its charged to 163 psi and it sends the pellet out at 900 fps we know is a springer sends the pellet out at the same 900 fps we know the springer has the same amount of psi behind the pellet . It doesn't matter how much psi the cylinder is producing all that matters is how my psi is in the barrel behind the pellet and that's 163 psi if the gun is chrony at 900 fps with a 10 grain pellet and the pcp with a gauge proves it . The question was How much air pressure in a springer ? The answer would have to be Its according to what the crony fps reads with a certain weight pellet . So for example if the springer that used a 10 grain pellet chronyed out at 900 fps the answer would be it takes 163 psi in the barrel to achieve 900 fps with a 10 grain pellet . If someone ask that same question about a pcp you would have to give the same answer . Its really as simple as that .
If you pump the pcp gun thats in the video above up to 163 psi and stop it will send a pellet out of the barrel at 900 fps .
I think anyone can do this test that has a pcp . Fill a empty cylinder to 163 psi put a 10 grain pellet in it and do a chrony test and see what happens .