JSB Exact Jumbo Monster .22 1.645 grams Ballistic Coefficient

[Air Rifle Activities]

Hi everyone.

Does anyone have info on the BC of the JSB Exact Jumbo Monster .22?
Thanks in advance.

[rsterne]

ChairGun quotes it as being 0.044, but no velocity is given.... I would think somewhere between 0.04 and 0.05 would be about right, depending on the velocity (over 900, use the lower value).... For most JSB Exact series pellets, if you use a Form Factor of 1.5 you will be close at about 800 fps average velocity to target.... Calculate the Sectional Density and divide by 1.5 to get the approximate BC....

Sectional Density = Weight (gr.) / 7000 / cal^2

BC = SD / FF

For the Monster.... 25.4 / 7000 / .22 / .22 = 0.075.... 0.075 / 1.5 = 0.050

Bob

[Air Rifle Activities]

Thanks for the comprehensive answer, Bob
I went through the Chairgun pellet database and could not find these... May I have a link if you found this info on the web?

[rsterne]

It's in my Chairgun database.... Have you updated yours?.... Pretty sure I didn't add it myself....

Bob

[Air Rifle Activities]

Yes, I just checked for updates again, nothing.
The only available Monster is in .177.

[rsterne]

Sorry, I don't know where I got that data then.... I know I did some limited testing a while back, that probably included that.... I may have taken an average of the values I determined.... BC varies so much depending on the velocity you measure it at, it is really only valid for the conditions used to determine it....

Bob

[Joe Brancato]

If somebody sends to me a list of all the JSB BC's, I'll post it on a website.

[JungleShooter]

If somebody sends to me a list of all the JSB BC's, I'll post it on a website.

Here's a comprehensive BC table for .22 caliber, including some hard to find numbers of JSB Ultra Shock Heavy, Monster, and Beast:   

https://www.gatewaytoairguns.org/GTA/index.php?topic=149053