GTA
All Springer/NP/PCP Air Gun Discussion General => PCP/CO2/HPA Air Gun Gates "The Darkside" => Topic started by: DarkRattle on March 31, 2017, 02:38:43 AM
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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!
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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.
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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.
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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 8)
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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 8)
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
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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.
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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.
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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
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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..
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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.
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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+
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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
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My Wildcat averages 825 FPS, 24 shots at 12" from the chrony. 85 degrees
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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?
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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
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Good choice, for the most part....
Bob
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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 :D . Unless you were at a zoo; in which case you could end up staying behind bars...
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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
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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
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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.
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Had planned on trying them in my Mrod started casting the 40g BBT instead...
will eventually try some I think should get around 800 fps... probably as high as 880 switching to a 10# spring..?
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Shooting Heavies from my .25 BSA at around 890 fps, 1/4" ctc groups at 50M and around 1" at 100M. POI shifts in varying wind conditions are around 4" at 100M :(
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Considering wind shifts at 100 yards can be as much as a foot with some pellets, 4" is pretty decent (~1 MilDot), depending on the windspeed....
Bob
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Considering wind shifts at 100 yards can be as much as a foot with some pellets, 4" is pretty decent (~1 MilDot), depending on the windspeed....
Bob
With decent bullets the shift would be down to one third or fourth of that. JSB King Heavy is a good long range pellet but unfortunately it's no match for bullets.
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Agreed, I was talking about pellets.... a decent bullet is FAR better.... The wind drift, at the same velocity and range, is inversely proportional to the BC....
Bob
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I had a chance to test the BC of the 34.2 gr. King Heavy Mk II's today at 50 and 100 yards.... I used my Hatsan, tethered at 2900 psi, so the velocity was slightly less than the gun is capable of mid-string at about 2500 psi.... I had the Chrony set at 1 yard, 50 yards, and 100 yards, so the first increment was 49 yards, the second 50 yards, and the total 99 yards.... I shot 9 shots (1 clip) at each range, and if I got an ERR, I shot again.... The average muzzle velocity was 915 fps with an ES of 11 fps.... The 50 yard average velocity was 791 fps, with an EX of 25 fps (if I throw out the fastest two and the slowest two and average the other 5, I get 789 fps with an ES of 11 fps).... and the 100 yard average velocity was 688 fps with an ES of 33 fps (if I throw out the fastest two and the slowest two and average the other 5, I get 687 fps with an ES of 25 fps)....
Using ChairGun, corrected for my altitude (750 m = 2460 ft.) and barometer (1007mB), I get the following BC's.... The range is because of the different numbers if I throw out the high and low velocity shots, which really makes little difference).... All the BC's are calculated using the GA Drag Model in ChairGun....
49 yd. increment, 1-50 yds.... 0.0405 - 0.0412
50 yd. increment, 50-100 yds.... 0.0378 - 0.0388
99 yd. increment, 1-100 yds.... 0.0394 = 0.0398
Average of all BC's calculated.... 0.0396, let's call it 0.04.... This is significantly less than what others are reporting.... and I got raw values of right around 0.05, but once corrected for my altitude, that's what I got.... Since I was shooting under my conditions, however, the trajectory I saw matched what ChairGun predicted for a BC of 0.05 (at sea level)....
Bob
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There are of course these Labradar measurements from Yrrah:
(http://img.photobucket.com/albums/v392/Kyogle/Labradar%20Superimposed%20graphs%20for%20Heavy%20and%20light%20JSB%20Kings%20Cd_zpski6bkrwx.jpg)
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So can anyone estimate what is the minimum velocity you need to shoot these 33 grain pellets to achieve significant/meaningful benefits of the higher BC? 850? 880? 900?
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Their BC will be superior to the 25.4 gr. Kings at virtually any velocity.... If you are shooting at 100 yards, I would suggest the optimum velocity for minimum wind drift will be about 850 fps, the same as any other Diabolo pellet.... However, the penalty in drift is miniscule at 900, or even 950 fps.... I would use anything between 850-950 providing you are not seeing spiraling at the longer ranges in your barrel.... Realistically, if your gun is too powerful for the 25.4 gr. Kings, then use the Heavies, providing they are accurate for you....
Bob
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There are of course these Labradar measurements from Yrrah:
(http://img.photobucket.com/albums/v392/Kyogle/Labradar%20Superimposed%20graphs%20for%20Heavy%20and%20light%20JSB%20Kings%20Cd_zpski6bkrwx.jpg)
Those graphs seem to match my theory that as velocity goes up the pellets skirts are feeling less drag and therefore provide less drag stabilization... exactly when and how will vary with head shape waist and length... about 700-750 fps in this example it goes back up after that...
I feel that is drag at the head also and due to double the speed quadruple the drag...
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Their BC will be superior to the 25.4 gr. Kings at virtually any velocity.... If you are shooting at 100 yards, I would suggest the optimum velocity for minimum wind drift will be about 850 fps, the same as any other Diabolo pellet.... However, the penalty in drift is miniscule at 900, or even 950 fps.... I would use anything between 850-950 providing you are not seeing spiraling at the longer ranges in your barrel.... Realistically, if your gun is too powerful for the 25.4 gr. Kings, then use the Heavies, providing they are accurate for you....
Bob
Hmmm...Don't know if I can get to 850fps with the MKIIs with my regulated gun, but worth trying to see and check for accuracy.
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I don't think you can draw conclusions about the drag of a skirt from LabRadar data over such a limited velocity range.... I have done conventional Chrony testing of skirted pellets at higher velocities, and I can tell you for a fact they have HUGE drag above Mach 0.9....
Bob