EDgun .22 vs .25 video part 2 finished
This video went much longer than I had originally anticipated. It kind of became a monster. I hope you enjoy it
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Great videos and good discussion… for me the #1 outcome was a decision to buy this (and couldn’t be more happy! It’s as important as barrel & scope):
(pic taken today)
Thanks! Mine came in at 975 so I will be dialing it back.
Cheers! :18:
Yes, it had the best BC while still being stable in flight.
Revisiting this since I have a .25 Maddy now.
KS, do you feel that 925(ish) is the optimum velocity for the JSB 25gr heavy’s?
Thanks
DT
you won’t be able to get reply from Pavel more than the 1st time,,, :rofl: :rofl: :rofl:
Does he wear a beret too? :rofl:
Here is what I found:
http://www.gatewaytoairguns.org/GTA/index.php?topic=14735.0
In Strelok Pro you can put BC in the form of pairs: BC value, velocity value.
As of JSB – yes, I’ve been to them a couple of times. If you have any questions you can write to Pavel Kolebac: kolebac@schulzdiabolo.cz
Sozer’s Airgun MythBusters!
Another great vid Keyser, very time consuming for yah thanks for making !!
Seem we’re still very dependent on the pellet manufacture to putout quality goods constantly, while keep pushing limit of the Diabolo design …… ..
~ Greg
Pip I do not have an indoor facility to check my BCs. After years of 1000 yard shooting one thing I know for sure is BC is not a constant. I honestly do not find much use for a homogenized BC calculation calculated in perfect conditions since I will never shoot indoors. If I were like Robert competing at his 100 meter indoor matches I would know that information. I am not convinced that the form function used for diablo pellets is 100 percent verified and accurate. There is very little data published about the form factor GA and at what speed it was tested. There are end user test like me on GTA that have put a lot of work in but I cannot find much information from JSB. I would love to talk to the head of external ballistics at JSB. I know shooter3 has been to JSB, maybe we could get them to post here?
Keyser,
could you check to what degree the BC given by the pellet’s manufacturer matches your BC measurement taken for example indoors?
Dan haha, you won’t see a video like this again from me for awhile. If I do another one it will be at the pellet’s optimum speed. The killer part of making that video was re-tuning the EDgun when I changed speed.
The shape of pellets kinda suck. They handicap the gun. The faster an object travels the more drag is placed on the projectile. At a point where the speed is transsonic air begins to act like a liquid on the projectile. The faster the object goes the more important shape of the object becomes. Remember back when you were a kid and you would play airplane with your hand out of the car window? Keep your hand profile small and you felt very little drag. Turn your hand flat and the air molecules would push your arm so much you were unable to keep it straight. That was at 60 mph. 900 fps is 613 MPH. The drag is tremendous on our little pellets. So the .22 shares the same exact shape as the .25 but it has a smaller profile.
Ballistic Coefficient = (Bullet Sectional Density) / (Bullet Form Factor)
Sectional Density is a number calculated from: weight of bullet in grains divided by 7000 (# of grains in a pound), then divided by the squared diameter of the bullet.
Form factor is a numerical figure that compares a projectile’s unique drag to that of a standard or reference bullet such as the G1 or G7 projectile. The lower the form factor of the projectile, the more efficient it is
Good stuff KS. Did not, overall, expect the .22 to do as good vs the .25. Does the length to diameter have something to do with this performance from the JSB 18.1?
Looking forward to the .25 vs .30 now! :rofl:
DT
Example:
@50 yards my calculated BC was .0429
@100 yards calculated BC was .0469
890 fps using .0429 predicted drop 150 yards 8.3 MRAD
890 FPS using .0469 predicted drop 150 yards 8 MRAD : this is the difference between a kill ,wounded, or miss
890 FPS BS .0429 @ 80 yards 1.9 MRAD
890 FPS BC .0469 @ 80 yards 1.8 MRAD : both are a kill shot
hope this helps
Thanks, that does simplify it a bit
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Saw one today at a local store called Scheels. Nice piece of kit. If purchased you get a $50 cash card. Vortex is making some good gear.