I do NOT agree that BC's are useless.
Problem is that people do NOT understandf WHAT they are.
BC's are SCALE FACTORS, if you cannot accept that, then read this first:
Just what the H---k is the "Ballistic Coefficient"?
Having said that, and from the time I started dabbling in ballisctics, I have used BC and non-BC driven methodologies, if you are not familiar with deceleration factors, you need to read this book:
Amazon.com: Modern Practical Ballistics: 9780961277635: Pejsa, Arthur J.: Books
Again, after much experimentation and when I drifted away from 1,000 yards shooting and other long range powder burning ventures to pursue the humble pellet, I came across another realization: The final shape of YOUR pellet depends on YOUR barrel.
Shooting at low energies (sub-12 ft-lbs) is when the differences between barrels are MOST obvious.
It also happens to be the energy slot where we DO shoot "Long range" (1½"Kz's @ 55 yards at 12 ft-lbs is the ballstic equivalent of shooting cantaloupes at distances out to 350 yards with a 7.62X51 NATO 147 grs. service load)
So, it is the most demanding discipline.
Between the fact that tables were developed in ONE barrel (not mine), shooting a pellet at a speed that perhaps I would never use (remember the 12 ft-lbs at the muzzle limit), and under conditions that probably were MUCH more controlled that what I would meet in an FT Match (basically weather caused/oriented), told me that the ONLY reasonable assumption when trying to get "good numbers" with relatively little data would be that "Nature CANNOT be discontinuous". And therefore, we needed a different approach that assumed NOTHING except the continuity of Nature itself.
And that is what drove the development of "PP-Calc"
Under PP Calc, YOU shoot YOUR pellet out of YOUR barrel at YOUR MV, using YOUR scope at YOUR LOS.
YOU choose your Zero (whether it is the first, second or the apex is absolutely irrelevant to the method).
THEN you shoot THREE ranges.
PP Calc will then CALCULATE FROM THE DROPS, THREE different BC's
YOU can then choose to use a weighted average, or a simple average to calculate the trajectory AND the wind drift.
Is it accurate? Yes if you feed it GOOD data. If not, the ID 10 T error pops up. Garbage in, Garbage Out.
The method does give you ways to "filter out" crazy data.
For example, you can look at the trajectory chart from ZERO (muzzle) to the end of the longest distance. If you note that the curve does not "match at zero" your LOS height, you adjust that because PP Calc needs the LOS height at the MUZZLE.
If you see a point that does not align to the trajectory, you re-shoot it. Perhaps the distance was not 37 meters, but 38, or 36.
If you do NOT see the BC's INCREASE slightly with the distance as the pellet slows down, then your numbers are suspect.
In short, it is a TOOL to analyze YOUR data, ratify or rectify and then take some numbers seriously.
Could we revert to Drag Coefficients per each range? Yes, but the "public" would have a hard time understanding that. BC's are so well known (even if they are grossly misused), that trying to "teach" Dc's became a casualty of the development process.
We had to discontinue and "un-publish" PP Calc because Android eveolved at such quick pace that it was impossible for my coder to keep up. But we are making an effort to get it updated and I think we will be able to publish it again soon, in a question of months.
It will still operate under the old rules and mechanisms, but it will be upgraded in many ways.
If you are interested, these links will give you an idea of what you can expect:
Pellet Path Calculator
Some of you have asked if the TRUE line of sight/Scope Height changes from venue to venue. The truth is that it does. And it all comes from the way scopes work. People think that the vertical...
www.ctcustomairguns.com
For those interested in maintaining privacy, here is the disclosure:
Privacy Policy for PP-Calc
PP Calc will NOT have any ads, and will NOT keep any information. It WILL have a modest cost, but most importantly, it will work for YOU.
Now, if you can put in the time to shoot EACH AND EVERY YARD, IN ALL POSSIBLE WIND CONDITIONS, then by all means you do not need PP Calc.
If you would rather get SOLID information from your Zero + Three more ranges and have a full ballistic solution, then PP Calc is for you.
As you will read from my note about "What the H---ck is a a BC"? you will realize that UNLESS you give the system ACCURATE information, the output CAN be at the same time, good and bad.
For example, you can calculate your ballistic solution for a "supposed" or "assumed" MV. YES, no problem, EXCEPT that then, if the real MV is different from the TRUE MV, then the BC's will not be correct and the Wind Drift will NOT match reality. Because you have come up with a TRUE SCALE factor for your "imagined" MV and because gravity is constant, the drops from zero will be true, but NOT the drifts (and that is assuming you can gauge well the wind to within 1 km/h)
IF, all your data approaches real well what YOUR truth is, then the numbers will be solid because we are NOT working in the quantum world where things jump from one state/position to another.
I repeat: at OUR scale, Nature is continuous.
When I was shooting 45 cal. , 500 grs. lead slugs at 1,240 fps on targets that were 28" across and 1,000 yards away, the BC's made a lot of sense. The "master" projectile was not too far from mine, the speeds were not too far from mine, therefore, it made sense.
There is NOTHING in common between an 8½-10½ grs. waisted and skirted pellet at 700-800 fps to the "standard projectile" in the Krupp/Majewski/Ingalls tables.
So, are BC's relevant/useful? YES, but ONLY as a TOOL and when properly applied.
Keep well and shoot straight!
HM
. At that distance it will still blow through 5/8 plywood no problem, tested that too. What is the BC of my Mrds? No idea. For me Airguns are fun, semi-accurate math formulas not so much.
Yes, sir I can see how that would work.
Until the day their work will bring results for us, I have been thinking of a practical solution to the discrepancies between the BC based on the GA drag model and the reality on the range and in the field. 
