GTA
All Springer/NP/PCP Air Gun Discussion General => Air Gun Gate => Topic started by: EJB on September 18, 2011, 01:39:53 PM
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Some place on the net I seem to remember an article about the best
fps for each pellet. Am I dreaming or does it exist?
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I've done some experimenting with .22 cal JSB Exacts of various weights.... but even with those I wouldn't be able to state an "optimum" velocity.... and I've never tested other types in any serious manner.... Here is an approximation of how the BC varies with velocity for the Exacts....
(http://i378.photobucket.com/albums/oo221/rsterne/Important/JSBBCs.jpg)
You can see that the heavier the pellet the higher the velocity where the BC peaks.... The lines in that graph were drawn by hand as a "best fit" for the data which was only a few (4-6) data points for each pellet.... so it can't be relied on to accurately predict the BC for a given velocity.... I just drew it to show the trends....
Note this has nothing to do with the accuracy, just the BC.... I understand that wadcutters are the most accurate in the 550-650 fps range, and then only out to 20-25 yards or so.... Round nosed pellets remain the choice for long range shooting....
Bob
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Keeping most pellets below the speed of sound, say 900 to 1000fps will help with accuracy. The 800 to 900fps is usually best for round nose pellets. Target rifles shoot wadcutters at 550 to 650 for maximum accuracy as stated above! Typically more pellet speed equals less accuracy. ;)