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- Joined: October 11th, 2016, 2:27 pm
600fps at 100 yards with a JSB 18.1 doing an average of 861fps over a 50 shot string. That 861fps is tested by a Chronograph at unknown distance from previous owner. I don't have a chrony and wouldn't be willing to risk sending it through at 100 even though this exact information put into Chair Gun Pro has me DEAD on nuts at 100 yards. Taking the cap off of water bottles 6x magnification hold 3rd mil-dot right on top of cap....1 foot is adequate. Bigger bores and/or higher velocities may need more.
Expect to lose about 1 to 4fps per foot.
Still getting 600fps and retaining, what, 14FTLBS? From what I'm seeing, there is a huge variance you can see in fps before POI change at 50 yards. I believe I've been told a 40fps variance will cause a 1/4" drop at 50 yards.
So are my figures wrong or can some pellets like JSB 18.1's retain more energy/velocity and loose less than 1fps per foot?
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