I measured (1000) 139laps, and (500) 105VLDs,, once (~10yrs ago).
It took a lot of work, one-off specialized jigs, every tool we have today, and custom software. Matching BC took additional efforts.
Given results, I decided not to do it again -until laser scanning technology meets needed resolution, flexibility, and cost.
The benefit in that effort was not so much ballistic gain, but in the learning about it.
I'm declaring now, this is still an abstract, due to lacking technology, and we're better off not pissing with it yet.
Out of what I measured there were only ~20 with attributes so bad as to cause flyers at distance(mathematically). That is, after meplat trimming and/or pointing. But then combine SD from the load, and system inconsistencies, and it makes sense that folks would report no observed difference from unsorted bullets -in lot. At the same time, it makes sense that those investing so much effort would be convinced of differences. That's a human thing..
If I were a 1Kyd BR shooter, I would not want to go to the line with any of those 20 offenders. I would set up a station, no matter the cost, to find them efficiently. After all, my time is expensive(to me).
Back to what I measured. I could have culled bullets on any of various parameters, BT angle, end diameter, BT length, bearing diameter and length, ogive radius, nose length, meplat diameter, OAL, weight, jacket thickness variance, core height. But in that, if separating by single attributes, I would have removed many bullets actually matching the BC mean in lot, and potentially kept some of the bad guys...
Don't do that.
I had set up a spreadsheet to enter parameters and run a macro to calculate BC of each. Only then could I see what I had, and it was nothing to lose sleep over. Shorter base, longer bearing, shorter nose, .xxx meplat, .yyy weight, zz.zcals ogive radius, botta bing -> ~matching BC, or I could match with a touch of pointing or trimming.
Each thing contributes toward the end, which is BC (or overall drag). For matching here you need to take all into account before separating.
A lot of folks are separating with groups of parameters, like 'base to ogive' while never calculating end results, and missing the biggest single affect in variance(meplats). Perhaps a coincidence that meplats are not easy to measure.. I see folks trimming meplats from all the way back at the base. This is not producing same meplat diameters, but causing same OAL.. Some trim from ogives, but they had failed to qualifiy their ogive datums first, again not meeting the very goal of trimming. Some weigh only, the grand daddy of shortcuts to no where.. Then bearing length! Who cares about bearing length in itself? I don't, it means nothing in particular.
To sum it up, wait a while on this. Focus on bigger fish. Someday bullet makers will use technology to match all bullets in select lots, and sell them to us at a little higher cost. If I were a bullet maker this is what I would do.
It took a lot of work, one-off specialized jigs, every tool we have today, and custom software. Matching BC took additional efforts.
Given results, I decided not to do it again -until laser scanning technology meets needed resolution, flexibility, and cost.
The benefit in that effort was not so much ballistic gain, but in the learning about it.
I'm declaring now, this is still an abstract, due to lacking technology, and we're better off not pissing with it yet.
Out of what I measured there were only ~20 with attributes so bad as to cause flyers at distance(mathematically). That is, after meplat trimming and/or pointing. But then combine SD from the load, and system inconsistencies, and it makes sense that folks would report no observed difference from unsorted bullets -in lot. At the same time, it makes sense that those investing so much effort would be convinced of differences. That's a human thing..
If I were a 1Kyd BR shooter, I would not want to go to the line with any of those 20 offenders. I would set up a station, no matter the cost, to find them efficiently. After all, my time is expensive(to me).
Back to what I measured. I could have culled bullets on any of various parameters, BT angle, end diameter, BT length, bearing diameter and length, ogive radius, nose length, meplat diameter, OAL, weight, jacket thickness variance, core height. But in that, if separating by single attributes, I would have removed many bullets actually matching the BC mean in lot, and potentially kept some of the bad guys...
Don't do that.
I had set up a spreadsheet to enter parameters and run a macro to calculate BC of each. Only then could I see what I had, and it was nothing to lose sleep over. Shorter base, longer bearing, shorter nose, .xxx meplat, .yyy weight, zz.zcals ogive radius, botta bing -> ~matching BC, or I could match with a touch of pointing or trimming.
Each thing contributes toward the end, which is BC (or overall drag). For matching here you need to take all into account before separating.
A lot of folks are separating with groups of parameters, like 'base to ogive' while never calculating end results, and missing the biggest single affect in variance(meplats). Perhaps a coincidence that meplats are not easy to measure.. I see folks trimming meplats from all the way back at the base. This is not producing same meplat diameters, but causing same OAL.. Some trim from ogives, but they had failed to qualifiy their ogive datums first, again not meeting the very goal of trimming. Some weigh only, the grand daddy of shortcuts to no where.. Then bearing length! Who cares about bearing length in itself? I don't, it means nothing in particular.
To sum it up, wait a while on this. Focus on bigger fish. Someday bullet makers will use technology to match all bullets in select lots, and sell them to us at a little higher cost. If I were a bullet maker this is what I would do.
