JSB Beast ballistic coefficient?

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Lou

Member
Oct 6, 2015
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Hey guys,

I got my Diana P1000 to shoot these at 260 m/s for 75 very consistent and accurate shots, I am very happy with the result and the punch these pellets give but I can't find the ballistic coefficient for these. I have a barrel mounted chronograph so calculating the BC is not possible for me right now. Does anybody know the BC for this pellet?

Thanks,
Lou
 
Lou:

If you know your muzzle velocity, you can calculate the BC if you set targets at known distances and measure the drop...Plug different BC's in Chairgun or Strelok until you get the drop you shot...

I started a simple thread about this...You may find it interesting:
http://airgunnation.dev/topic/strelok-chairgun-other-programs-and-ballistic-coefficients/

Merry Christmas!

AZ

PS. Just guessing I believe that your BC will be in the .030's range
 
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A more accurate way to determine the BC for shooting any pellet in your airgun, assuming you have a couple of consecutive consistent velocities, is to put your Chrony or velocity measurer at 2 different distances and collect velocity samples. Having the muzzle velocity and another velocity at 10 yards or 20 yards or some other known yardage, you can input BCs into ballistic software and keep computing the results, until you match the velocities at the 2 distances used in your testing. BCs will vary from barrel to barrel, but not significantly. There is a formula to compute the BC which uses 2 velocities, the temperature and altitude, but it is very very long, and complex and will work in spreadsheet software, such as Excel, Lotus, or others, but I don't recommend it unless you are a very mathematically inclined. There are a number of ballistic softwares on the market. I can't recommend one specifically. The highest BCs I recall computing are from the Crosman .25 cal and the H&N Baracuda's. These have higher BCs than the typical rounded domed pellets mostly because they have pointy domes. 
 
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You can use chairgun pro on the desktop (free) to calculate your BC. Go to tools drop down and hover over "calculate bc from" and choose "poi at range' and fill in the information. Pretty easy and gets you pretty close. In order to be accurate you have to to be real steady at your zero and make sure you are shooting consistent in one spot so your air pressure is crucial on every shot unless you are shooting a regulated gun. You also need accurate measurement of the drop or the calculation will be of no value.

Then I would shoot a few further distances to check the BC. So you could zero your gun at 30 yards and then shoot at 50 and 75 yards to measure the drop from 30 yards. You will need a chrono to input the muzzle speed for each shot.
 
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I don’t know the bc of jsb’s Beast. But I can shoot them way faster than any other pellets. 1070fps out of a Warp Cobra. This is because they are basically spin stabilised. Don’t have much of a skirt. I’ve shot a crow in one eye with these at 50yrd.

They’re extremely accurate out of the streched TC barrel at very transonic speeds. You’re not getting much of vacum with these pellets. In my barel they tend to be most accurate and more quiet at 1040fps, haven’t tried them below a 1000 fps... I own many airrifles and all of them are tuned way sloower except the Sinner, that shoot solid lead. 

I’m not an expert but I usually shoot slower than 900fps?! I tune my own guns, these pellets are great for hunting and can shoot moa @100 yrd.

Eyeshot: https://instagram.com/p/BiwNWcmApIQ/
 
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BC for the JSB Beast in .22
There isn’t much info out there. I found a couple of tests done by Airgun Shooting And Related Activities.

2017: 36FPE gun. Distance 47y
BC = 0.046 (GA)
Source: https://www.youtube.com/watch?v=JpsJPgwNrOY

2017: 59FPE gun. Distance 46y
BC = 0.051 (GA)
Source: https://www.youtube.com/watch?v=kKhQ0RdVtnU

I shows like so many other tests that BC does change with velocity.




For a comprehensive list of BC numbers in .22 cal, cf. https://www.airgunnation.com/topic/bc-table-22cal-comprehensive-internet-wide-collection-of-ballistic-coeff-data/

Matthias
 
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