Calculating and Using Drag Variability (EXTREME RELOADING Special Edition)

The Drag Coefficient tells us about a bullet's aerodynamics and resistance in flight. We can calculate Drag using data collected by a LabRadar. Drag variability tells us conistent or uniform our bullets are. In this video, we will talk about how to calculate drag using a downloadable spreadsheet we created and how to apply the results.
Timeline:
00:00 - Intro
06:21 - Drag coeff. spreadsheet
11:58 - Results
17:01 - Drag variability and precision
Links:
Feldmutze channel: / @feldmutze
XLS Worksheet on Dropbox: www.dropbox.com/scl/fi/2iqy6a...
Applied Ballistics paper: appliedballisticsllc.com/wp-c...
Test with ogive and weight sorted bullets: • Extreme Reloading: Tes...
Bullet run-out: • Extreme Reloading: Tes...
Calculate BC: • EXTREME RELOADING (SPE...
30-shot group Sierra TMK: • EXTREME RELOADING Spec...

[@BobJones-zw3ui]

Have always wondered about these bullet variables - well done💥👍🇺🇸

[@sdkweber]

Thank you. I appreciate you watching and posting.

[@R32R38]

Good stuff to know.

[@sdkweber]

Thank you. And thanks also for watching

[@rangergreen3995]

Keith...do you compare the results of your tests against a control group? For example, comparing the test results from a selected group (consistent weight/length) against a group taken straight from the box.
I really enjoy your videos and the analysis that you do. I am conducting my own tests using a Labradar.
Thank you and best regards,
Gerry

[@sdkweber]

Hello Gerry, I have not done that test but you have a good idea. The control group could be selected using bullets that are physically as consistent as possible then loaded and shot to calculate drag, BC, and variability of drag. To create the control group one could use bullets with the same weight, same overall length, and same base to ogive length. In my experience sorting bullets a person would need to sort through a lot of bullets to come up with a respectable control group. Thank you for watching and posting Gerry.

[@joearledge1]

I wonder if you could use this same experiment to see if sorting bullets by weight, or base to ogive, or bullet overall length, or diameter(shouldn't be much variation here, +/- 0.0002" I'd assume, but I'd also assume that it's the most critical dimension), or completely unsorted. The hypothesis being that whatever sorting method is best, will have a statistically significant higher BC relative to the other groups. Basing it on BC calc should make the conclusions independent of any marksmanship variability. It would be interesting, but definitely a tedious and time consuming experiment.
In addition to all of the other videos that suggest that concentrisity/ run out doesn't matter, Brian Zolnikov is doing the most scientific study of run out yet, and his preliminary results are highly suggestive that run out doesn't matter. If you haven't seen his channel, I'm sure you'd love it. Anyway keep up the good work Sir

[@sdkweber]

I am just now catching up as I have been out hunting. I like the idea of sorting bullets and testing to see how they perform (precision) and how consistent the drag coefficient and BC is on uniform bullets vs. non-uniform bullets. I have done some tests like this but did not check drag variability or BC. I might have the Labradar results from these tests though which will make it easy.
I believe I have watched some of Brian's stuff but am not certain. I will do a search and check it out.

[@jasonrad9332]

👍🏻

[@sdkweber]

Thanks Jason

[@jackboshoven8316]

Curious why you choose to aggregate all the data for each bullet. I would think that calculating the average drag coefficient from the data for each shot, the SD and then comparing that set of ten averages and SDs against each other would be a way to potentially see if the drag coefficient between individual bullets had any statistical difference. The drag coefficient should be essentially constant over the first 47 or so yards, therefore the uncertainty on the average drag coefficient for a single shot should give you an idea of the precision of the lab radar method if you will.

[@BobJones-zw3ui]

Post a vid jack.

[@sdkweber]

This is a good point and thank you for posting. Statistically I am interested in comparing drag variability between bullet types. The observational bullet type for this test is the 1) Berger, 2) Barnes, and 3) Sierra. To do this I need a large enough sample size to achieve "power of analysis". For that reason, I took all samples (10 shots for each bullet) and treated it as one statistical set.
I could also look at how much variability we have between each of the 10 bullets shot within a given bullet type. This would be a comparison within bullet types (previously I described a comparison between bullet types). Both are absolutely legitimate and the use of one approach or another is determined by the question being asked.
If you are interested, I could run the WITHIN test since I still have the data all very nicely organized. If could report that back to the comment thread if you are interested. Just let me know.
Take care and thank you for watching and posting.

[@jackboshoven8316]

For sure your comparison of the three bullet types is valid given your argument up front one certainly would expect consistency from bullet to bullet. I was just curious why not check the bullet to bullet just to see how well the data overlapped giving one an idea of how well the labradar is doing in collecting its data. Thanks for the offer to do the test I proposed. I do not shoot those bullets, so the data would not be useful to me. I will download your spreadsheet however and do "my" way of processing the data with the plethora of data I have for the bullet I shoot in my target rifle (6.5 CM). For my hunting rifles, I am happy with minute of deer at reasonable ranges (325 yards for me). I think I have only shot at deer type game over 150 yards less than 10 times over my 40+ year hunting career. Thanks for the discussion and thought provoking video.
Jack

[@sdkweber]

@@jackboshoven8316 Thanks Jack. Give it a try. I started the analysis we discussed and the Berger Classic Hunter is quite consistent... all but bullet #8 which exhibited higher than expected Cd. I will continue with the other bullets just out of curiosity.