JSB 18 jumbo heavy
hello friends, you can inform me ,what is the ballistic coefficient of the heavy 18-grain JSB 5,5 pellets? I need to insert the data in the chair gun
thanks
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I thought so too. I did the speed shecks on 2 different days. The first time, I used my Combro for MV and the Chrony for the 100 yards speed. When I plugged the numbers into Chairgun, I got a BC of.0440. The next time, I used the Chrony at 1 yard and 100 yards and got a BC of.0390. The difference between the 2 numbers is because the Combro gives muzzle speed and the Chrony at 1 yard gives a lower speed.
Chairgun has it preprogrammed in the system – they say .033.
I’ve also seen .036 and .038 from various online pages.
Crazy Tedd has the only tin of .044 bc JSB’s in the world. 😆
I took chrony readings at 1 yard and 100 yards on my .22 cal. Matador. I plugged the numbers into Chairgun and got a BC of .0439. That is for a JSB 18.1 pellet at 883FPS.
0.038 according to this: http://www.photosbykev.com/wordpress/2009/01/20/air-rifle-pellet-database/
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The value of the BC can change it’s not a fixed thing.
An other speed can give an other BC, or an other temp. if you are on sea level, or on high land you get different readings.