When I was calculating sight setting out to 1,000 yards, I found all the cast bullets were so close I just used the same coefficient for all.

My Lyman Cast Bullet manual  has BC's for some of their bullets and NOE has estimated for all(?) their designs.

Boomer,
That's exactly what motivated me - my engineering.  Although it's been several years since I applied the level of math that goes with a lot of BC calculations, thankfully there are plug and play programs and apps.

With the purchase of a LabRadar I realized I had the ability to generate a variety of velocities and the light bulb flashed.  I could calculate BC's

In my experiences, I have found the BC's that I calculate for large slow moving bullets (subsonic or transonic by 200 yards or less) didn't have as much effect as I was thinking (or hoping).  My calculated dope for these bullets were often skewed and things didn't happened as expected.  There's a couple of articles that mention multiple BC's for this sample...? so I tried their suggestions and my dope came a lot closer to actual results.  Add wind, density altitude, differences in lube, black powder variations, twist rates, barrel lengths, iron sights, the loose nut behind the trigger, and there's considerable more variables than a modern scoped rifle shooting a copper jacketed bullet.   

Unlike a high velocity round, (take my 6.5 VomHofe for example) - I get velocities, plug it into my program, get my settings, with small corrections for density altitude and viola` the bullet goes exactly where my dope says it will... 
 
I did similar experiments with 22rf and used the RA4 BC and out to 400 yards, my dope was right on... plugged data into my programs and the surprise I wasn't expecting- within less than a minute.

Aussie, 
It only my opinion, but the reason they don't publish BC's with every mold, the resources to calculate BC's has just recently become available at a reasonable cost.  The jacketed bullet mfg. needed to offer this to be in the race, but they sell a product, lots of the same product.  The mold maker, he sells a mold - does he make any money after that from that product, no.  Why invest more $$ in something he won't see any return on...  We may begin to see more info in the future but even for most, the outlay of $600 or $700 dollars for an instrument that is going to give a tidbit of info that still raises a question - not necessarily a great investment.
My 2¢ (more like 4 bits worth of opinion)
Greg 

I'd always questioned the BC variance based on different alloys.  Is it meaningful?

Rich

I've come to believe that there's very little difference between the BC of cast lead bullets for our long-range target rifles irregardless of the shape. Abought three years ago at Harris Minnesota, a good long-range shooter from Wisconsin was shooting during our practice day. Towards the end of the day, he said "I'm going to try some different bullets that a long-range muzzleloader shooter gave him to try". He was shooting paper patch and all he had to do was pull his bullet out of the end of his case and swap out these with the other bullets. These bullets had a large meplat and looked a lot like a blunt RCBS 740. Several of us were watching at this time and he said "what do you think I should do with the sights"? A buddy of mine said, "just shoot and we'll find out". He ended up shooting two tens and an X with the same weight bullet but a much different shape with no change in elevation. This was all at 1000 yards. I think bullet stability is much more important than bullet shape unless that bullet shape leads to stability.

Old-Win is correct in regards to stability. Back when we were spending allot of time shooting through the Ohler 43 Ballistic System. All though a bullet had a higher BC the time of flight in milliseconds would be quite abit longer than one with a lower BC. This could then be related to stability and or its in flight characteristics that would be slowing it down. So it is really not all about a bullets BC but it is actually all about a bullets actual time of flight. That is what one should actually be looking for when deciding on a bullet to use. A shorter time of flight to a target equates to having less time for a bullet to be exposed too the existing adverse conditions on a given day. And it also provides some valuable in sight on its actual in fight characteristics and stability and I hope all of this makes some sort of sense.

"If you meant, it does not matter how efficient a bullets design is, what matters is how efficiently it flies."

'''----how efficiently IT CAN BE MADE TO FLY

and therefore an efficiency of the bullet design can be determined for the purpose and conditions of use.

"Yah, I know.... picky picky"
beltfed/arnie