JSB King Heavy MKII .25 Ballistic Coefficient

[DarkRattle]

So I noticed no matter where I looked I couldn't find the ballistic coefficient of these pellets so I did my own calculation. .25 Wildcat shooting them at 797 FPS and they landed anywhere between 703-715 @ 50 yards, anywhere between 0.0516 -> 0.0599 and averaged out to 0.0520.

So the average ballistic coefficient is 0.0520, VERY impressive, darn thing beats more .30 and even some .35 BCs. Great pellet!

[rkr]

So I noticed no matter where I looked I couldn't find the ballistic coefficient of these pellets so I did my own calculation. .25 Wildcat shooting them at 797 FPS and they landed anywhere between 703-715 @ 50 yards, anywhere between 0.0516 -> 0.0599 and averaged out to 0.0520.

So the average ballistic coefficient is 0.0520, VERY impressive, darn thing beats more .30 and even some .35 BCs. Great pellet!

I think it beats all .30 and .35 pellets. It would be interesting to see the results if you could up the power to high 800 fps, that should be the sweet spot for 100M shooting with the pellet based on Yrrah's Labradar measurements.

[DarkRattle]

So I noticed no matter where I looked I couldn't find the ballistic coefficient of these pellets so I did my own calculation. .25 Wildcat shooting them at 797 FPS and they landed anywhere between 703-715 @ 50 yards, anywhere between 0.0516 -> 0.0599 and averaged out to 0.0520.

So the average ballistic coefficient is 0.0520, VERY impressive, darn thing beats more .30 and even some .35 BCs. Great pellet!

I think it beats all .30 and .35 pellets. It would be interesting to see the results if you could up the power to high 800 fps, that should be the sweet spot for 100M shooting with the pellet based on Yrrah's Labradar measurements.

I'd love to if I could, sadly I don't have an impact haha (curse you always out of stock!!!!), Ya I think 860 fps is the sweet spot, just an AMAZING pellet man.

[pepegraves]

Thanks for the data...I've been using them for over a year now...accurate and deadly from squirrels all the way up to deer 

[DarkRattle]

Thanks for the data...I've been using them for over a year now...accurate and deadly from squirrels all the way up to deer 

That's the point! I may or may not have dropped a deer with a headshot at 50 yards with the wildcat on my Africa trip.. If I did I'd tell you it worked great, passed through and through from temple

[Joe Brancato]

So I noticed no matter where I looked I couldn't find the ballistic coefficient of these pellets so I did my own calculation. .25 Wildcat shooting them at 797 FPS and they landed anywhere between 703-715 @ 50 yards, anywhere between 0.0516 -> 0.0599 and averaged out to 0.0520.

So the average ballistic coefficient is 0.0520, VERY impressive, darn thing beats more .30 and even some .35 BCs. Great pellet!

Thank you for the information.  From experience I have found that the .25 will easily hold up against the larger calibers in the wind. Now you have provided scientific proof.

[triggertreat]

This is all music to my ears.  I have a .25 Synrod waiting in a box for when I can get to it.  It's like when I got the .22. Can't wait to sling a MKII.

[ackuric]

Velocity, twist rate and the range you're shooting all have an effect on BC.

BC isn't static nor will every air rifle get the same bc with the same pellet.

I tested the BC for mkll's once and I was getting around .04-.042 BC but also was shooting them a bit slower in a stock m-rod (750ish) and was only testing the BC at 20 yards which is very favorable for a higher BC.

But lets generalize their BC for a sec since I'm sure all things being equal the BC will be very close in comparable setup+conditions.

mkll's @ 750ish = .042 BC avg (shot out of stock mrod)
mkll's @ 800ish = .052 BC avg (shot out of ? fx wildcat)
mkll's @ 850ish = ?
mkll's @ 900ish = ?

Would be fun to have more people participate. I'll be able to get some 850 readings in a couple weeks as I am modding my mrod's valve and am aiming to shoot the mkll's @ 850

[DarkRattle]

Velocity, twist rate and the range you're shooting all have an effect on BC.

BC isn't static nor will every air rifle get the same bc with the same pellet.

I tested the BC for mkll's once and I was getting around .04-.042 BC but also was shooting them a bit slower in a stock m-rod (750ish) and was only testing the BC at 20 yards which is very favorable for a higher BC.

But lets generalize their BC for a sec since I'm sure all things being equal the BC will be very close in comparable setup+conditions.

mkll's @ 750ish = .042 BC avg (shot out of stock mrod)
mkll's @ 800ish = .052 BC avg (shot out of ? fx wildcat)
mkll's @ 850ish = ?
mkll's @ 900ish = ?

Would be fun to have more people participate. I'll be able to get some 850 readings in a couple weeks as I am modding my mrod's valve and am aiming to shoot the mkll's @ 850

That's very true and that's exactly why I put FX Wildcat, I was more or less aiming at the FX Wildcat/Impact (smooth twist) in the 800 fps..

[DarkRattle]

Velocity, twist rate and the range you're shooting all have an effect on BC.

BC isn't static nor will every air rifle get the same bc with the same pellet.

I tested the BC for mkll's once and I was getting around .04-.042 BC but also was shooting them a bit slower in a stock m-rod (750ish) and was only testing the BC at 20 yards which is very favorable for a higher BC.

But lets generalize their BC for a sec since I'm sure all things being equal the BC will be very close in comparable setup+conditions.

mkll's @ 750ish = .042 BC avg (shot out of stock mrod)
mkll's @ 800ish = .052 BC avg (shot out of ? fx wildcat)
mkll's @ 850ish = ?
mkll's @ 900ish = ?

Would be fun to have more people participate. I'll be able to get some 850 readings in a couple weeks as I am modding my mrod's valve and am aiming to shoot the mkll's @ 850

That's very true and that's exactly why I put FX Wildcat, I was more or less aiming at the FX Wildcat/Impact (smooth twist) in the 800 fps.. Since 90% of people who shoot these pellets are using FX guns.

[WiseGuy]

Thanks for that info, planning on testing these out of my Wildcat .25 too as I put an order for them a few days ago.  I'll test them out of my REX too, it pushes 34 gr over 900+

[rsterne]

You have to keep in mind that the longer the range interval you use between the Chrony's, the lower the average velocity.... and it is the average velocity you need to use to compare the BC to.... For example, with a MV of 900 fps, if your second Chrony was at 25 yards, your average velocity might be 860 fps, but if you moved the second Chrony to 100 yards, your average might only be 750 fps.... I can almost guarantee (depending on the drag model you choose) that the BC you measured over 25 yards would be less than what you measured over 100 yards in that example.... even though your MV was the same.... I can absolutely guarantee that the Cd for a pellet will be worse at 860 than at 750 fps.... and at 950 fps a LOT worse....

Bob

[Berky]

My Wildcat averages 825 FPS,  24 shots at  12" from the chrony. 85 degrees

[DarkRattle]

My Wildcat averages 825 FPS,  24 shots at  12" from the chrony. 85 degrees

with heavies? Awesome did you tune the regulator or spring tension?

[DarkRattle]

You have to keep in mind that the longer the range interval you use between the Chrony's, the lower the average velocity.... and it is the average velocity you need to use to compare the BC to.... For example, with a MV of 900 fps, if your second Chrony was at 25 yards, your average velocity might be 860 fps, but if you moved the second Chrony to 100 yards, your average might only be 750 fps.... I can almost guarantee (depending on the drag model you choose) that the BC you measured over 25 yards would be less than what you measured over 100 yards in that example.... even though your MV was the same.... I can absolutely guarantee that the Cd for a pellet will be worse at 860 than at 750 fps.... and at 950 fps a LOT worse....

Bob

I calculate my BCs at the range I zero my gun @ which is 50 yards, I realize BCs change but chairgun pro only needs one static BC and I feel a 50 yard zero and BC testing is the most baseline (average) I can do

[rsterne]

Good choice, for the most part....

Bob

[subscriber]

I may or may not have dropped a deer with a headshot at 50 yards with the wildcat on my Africa trip...

Its not possible to drop a deer in Africa with an air rifle. 






An antelope, maybe  .   Unless you were at a zoo; in which case you could end up staying behind bars...

[Extreme .457]

    Love the MK II ammo. My FX Wildcat .25 is shooting them at 810 FPS
Gen 1 Marauder .25  835FPS  and my Condor .25 with Tx Tophat is pushing these bad boys at 930fps is where I found the best accuracy. The Condor .25 has taken fox, and several predators with this ammo.
Best JSB Pellet for my listed guns.

    Best of luck Fellas

[rsterne]

My Hatsan drives the 34.2 gr. MkII's at 960 fps (70 FPE) and can pull groups just over 1" at 100 yards at that velocity.... I see no signs of spiraling, or deterioration in accuracy at that velocity.... However, I'm sure the BC is no longer that stellar 0.052 that Yrrah got with his LabRadar.... Sorry, but I haven't got around to checking it yet....

Bob

[LDP]

I tried the mk2 in my recently bought wolverine but the wolverine does not like the mk2 but shoots the 25 gr. kings very good. I thought it was weird that the wolverine didnt shoot the mk2 better or at least as good as the kings.