Sully, bullet companies make them as consistent as they can, but they do not blueprint them.
They don't individually measure & separate each bullet into lots.
IMO, they should for any bullet designated 'MATCH', and of course those bullets should cost more.
This, so that a box of MATCH bullets stamped with a G1BC of .612, actually measure to a blueprint and hold a calculated G1BC of .612. Every external attribute of these bullets; End dia, Base length, Base angle, Bearing length, Bearing dia, Nose length, Ogive radius, Meplat dia, would fall within a declared tolerance -while combining to match in BC.
I seriously doubt this has ever happened, so if we're to get this we'll have to do it ourselves, and it is possible. But, the cost in it for us, is not yet viable.
A practical approach, Keyence IM-6500: https://www.youtube.com/watch?v=nBzI...endscreen&NR=1
Adapt this to an assembly line, and automate bullet separation into lots based on software set parameters/tolerances/ final calculations. ~$25K
If I stumble into the money, I'll do it & offer true MATCH bullets on the side to recoup costs.
But what we're doing today, manually with common hard measure, only brings more questions than answers. BEARING: Why would we care at all about this single parameter? And how are we actually separating this component in measure?
With a 105LAP giving me a calculated ICAO G1BC of .495 @ 3kfps:
-If I reduce bearing by 10thou -by extending base length and nose length 5thou each(all else same), my BC changes to .497
-If I increase bearing by 10thou -by reducing base length and nose length 5thou each, my BC changes to .492
-If I reduced bearing 10thou -by extending the nose alone by 10thou, my BC changes to .498
-If I reduced bearing 10thou -by extending the base alone by 10thou, my BC changes to .496
But, nose changes can mean ogive radius change and/or meplat dia change, and every 1thou of MD on this bullet means .003 in BC adjust -by itself.
So when you lump base and bearing length together into one comparative term, and nothing else, what could it possibly mean that you would base any action on?
Let's say it's an unknown, but small BC variance. Then what does it mean as far as friction?
I have not seen a test yet to isolate a ballistic affect from bearing born friction.
Have any of you?
I know that I could not see it using 139LAPs acrossed 20' screen spacing with an Oehler.
I know that I could not see it as seating force variance using an electronic loadcell built into my Sinclair expander.
It seems like the first action anyone takes after measuring bullets is to ask on a forum about their numbers.
Well, it's my contention that nobody knows what the numbers mean(until I'm proven wrong).
It's very much like weighing brass.. Another easy shortcut leading only to assumptions in meaning..