One minor point, don't take anything you see in YouTube videos as being correct. In the Ted's Holdover video if you look at the picture of his input data to calculate BC you will see he has the temperature as zero degrees F, yet he is walking around in shorts and a tea shirt and all the trees have their leaves. This is probably the main reason for his high BC, as the calculator would have worked using an air density way above reality and the calculated Mach number would also have been too high.Follow up.
I am playing with different things to see what it does to accuracy. I saw Gary Chillingworth on Shooting & Country TV channel have a bunch of weights on his one AA springer rifle to improve accuracy, so he says.
I put a piece of leather between my rifle's barrel shroud and the air tube and then tightly taped a bunch of mag wheel weights to it. I had to re-zero the rifle at 50 meter. Then adjusted 3.5 MRad up as always to shoot at the 100 meter target. The pellet missed the plate low. I then adjusted higher and higher to be about on target. The turret setting ended at 4.2 MRad to be close to POA, closer to the setting given by Strelok with the BC given by H&N. However, I still had to adjust the BC in Strelok to about .038, not precise. It is also known that a projectile's BC alters with speed, so I still don't know what the correct value must be.
As well as what Matt showed about JSB pellets in his video previously linked in the thread.
2.4 Lessons Learned from Ballistic Coefficient Testing - Sierra Bullets
www.sierrabullets.com
Ted from the channel Teds HoldOver also found different POI with increase of speed with his FX and slugs. He also at first concluded that the BC increased but in the comments and elsewhere here on AGN is was concluded that it was barrel harmonics causing the different POI and not the BC per se. I don't know what Ted's final conclusion was after the video and comments. Video below.
My conclusion is that it happens because the barrel is now stiff with all the weight and tape and don't move as much causing it to have a different POI. Without the weights the 3.5 MRad setting can only be because of barrel harmonics causing the pellet to shoot higher than what Strelok is calculating and I had to compensate on the turrets for it by dialing less MRad upwards.
The problems with the extra weigh is that the group open up a lot and that the rifle is now heavier and uncomfortable to carry in the field if I want to. So, knowing this I removed the weights and leather again. The leather was to prevent the tape to close the gap between barrel and tube. The thing is that I don't know if there is a way to compensate for it in Strelok other than adjusting the BC as I did before.
Another question, will a barrel tuner correct the harmonics to:
(1) Bring the dial setting to what it must be?
and /or
(2) Will a barrel tuner improve accuracy?
Both that questions I can only know the answer to if I buy and install a barrel tuner and test it. I did see it improving accuracy on a FX in a video as below from Airbuks
Video from Teds HoldOver:
Video from Airbuks:
As for Matt Dubbers videos, because he appears to know very little about ballistics or aerodynamics, the videos on pellet flight or stability contain a large number of mistakes. The worst one was his explanation of pellet aerodynamic stability, which was quite frankly rubbish and one of the reasons I produced a series of threads on pellet stability to try to get the facts out to shooters.
G1 is not a suitable reference drag law for pellets. Ga and GA2 were developed specifically for diabolo pellets. Using G1 gives low BC values at high speeds, as the reference drag law increases more slowly with Mach number compared to diabolo pellets. For slugs, it is the opposite way round, using the G1 drag law gives high BC values at high speeds as the slug drag increases less with increasing speed until a critical Mach number is reached. For slugs, use SLG0 or RA4 reference drag laws, unless they have a boat tail where SLG1 may be better.
Upvote 0
If you can, measure the velocities with a chrony at several different ranges (10-15 shot averages), especially where the projectile is flying at high velocities close to you, maybe: 0m — 15m — 30m — 60m — 100m. 
