Since you are limited to "off the shelf" pellets, it is mostly a matter of finding the best combination for YOUR gun.... IIRC, the last EBR was won with a .25 cal shooting 34 gr. JSBs, because they have a superior BC to any of the .30 cals.... If you can find a gun that shoots the 25.4 gr. JSB Monsters with lights out accuracy, they would also be a good choice.... In theory the 34 gr. Beasts should be even better, but very few barrels shoot them well, and the BC doesn't appear to be any better than the Monsters....One thing to try is very slow twist rates, at least 100 calibers, and up to 200 calibers per turn.... ie 25"-50" twist in .25 cal.... Diabolo pellets need VERY little spin to remain stable, and at long ranges too high a twist rate encourages spiralling.... In addition, the faster you spin a pellet (or slug), the more "aerodynamic jump" (vertical deflection in a crosswind) you will get.... Don't be afraid to work on getting a .22 cal to shoot competitively at the EBR.... but be prepared to try several custom barrels until you find that magic combination of pellet and barrel....Bob
Drop matters very little, because you sight to allow for it.... Put in a 10 mph crosswind and see what the differences are....
Also, you have to realize that it takes a much more powerful gun to shoot a 25 gr. pellet at 850 fps than an 18 gr. (both in .22 cal).... In fact, a gun that will shoot a 25 gr. at 850 will probably drive an 18.3 gr. at over 950 fps, at which point it would have the flatter trajectory.... However, since wind drift with pellets increases over about 900 fps, the 25 gr. will have a lot less drift....
The 0.062 BC you used for the 34 gr. .25 cal King Heavies is pretty good, I have never seen it rated that high.... HAM show it at only 0.046....
Most round nosed pellets won't have a BC higher than the Sectional Density divided by (a Form Factor of) 1.5.... That would be 0.054 / 1.5 = 0.036 for the 18.1 gr. JSB Heavy (which I know is right).... 0.075 / 1.5 = 0.050 for the 25.4 gr. Monsters.... and 0.078 / 1.5 = 0.052 for the 34 gr. King Heavies.... It would work out to 0.071 / 1.5 = 0.047 for the .30 cal Exact 44.8 gr.... These are just approximations but I have found them to be pretty close in the real world.... IMO you will find very little difference in the BC between the 25.4 gr. Monsters in .22 cal, the 34 gr. King Heavies in .25 cal, and the 44.8 gr. Kings in .30 cal.... They are close enough that how you read the wind will be MUCH more important.... Bob
Note that the minimum drift occurs between 800-900 fps, and above that it increases.... In addition, a lot of guys find the best accuracy at just under 900 fps (880 seems a common number with a lot of pellets).... but it really depends on your combination of pellet and barrel.... Likewise, a lot of guys find pellets spiralling (corkscrewing) at velocities over about 950 fps, but that IMO is largely because for the most part our twist rates are too fast.... Only experimentation will allow you to find your best combination....
I was not aware of the 2019 winner.... but it kind of shows the point that caliber and pellet weight are not important, it is only the BC (and skill) that matters.... Of course the BC = SD / FF, and the Sectional Density is weight (lbs) / caliber^2.... Find the velocity where your gun is the most accurate and stay with that.... If you end up using 1000 fps, and get 10% more drift because of that, but your BC is 10% better, that will cancel out.... Just remember that wind drift does NOT decrease with speed, once you enter the Transonic region (over Mach 0.8 = 900 fps) because the drag increases so quickly there.... It is the time of flight difference between your pellet (at your velocity) and what it would be in a vacuum (called the lag time) the governs drift.... The more drag, the greater the lag time, and the greater the drift....Bob