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All Springer/NP/PCP Air Gun Discussion General > Air Gun Gate

Need help caculating efficency

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JPSAXNC:
I'm fiddling with my bull puppy again, I have some strings and I wonder if you could tell me what the efficiency is. I'm using an 11" barrel ,22 cal, using the crosman 14.3 grain cphp's, the reservoir capacity is 64cc's the charge pressure is 2600 psi and the end pressure is 1700 psi.         String one, 734 734 741 738 740 743 735 738 745 741 742 739 744 743 741 739 741 741 741 738 741 740 740 733 737 734 735. 27 shots av. 739fps. Second string, hammer spring adjuster screwed in .023 further 747 744 746 741 746 745 742 745 742 744 744 743 743 747 744 744 745 745 739 742 735 740 740 745 739 737 738. 26 shots av. 742fps. Thanks James

JPSAXNC:
I found Bob Sterne's calculator for Hard Air Magazine. 1.9 fpe/ci. for the first string if I did it right.

rsterne:
Air used = 242  std. CI....

Total FPE = 468 FPE....

Efficiency = 468/242 = 1.93 FPE/CI, so you are correct, James....

Bob

JPSAXNC:
Thanks Bob.

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