Is the Ballistic Coefficient Accurate?

[HappyHellfire]

Look at the reduction in drag for the 6.5 Creedmoor/PRC design. I think I have solid ground to stand on here.

 

[HappyHellfire]

lol. Not saying it won’t work, but it would sure make reloading interesting. lol
Dave

I'm using standard loads with very little case intrusion. I use regular old RCBS reloading gear.

 

[HappyHellfire]

What is needed here is a verified side by side test. Your new bullet design against say three of the top bullets same Cal. and weight shot at 500 out of the same gun. Target always tells the truth!

I love this idea.

 

[Thauglor]

This whole thread looks like you are selling snake oil.

You don't think any of the current manufacturers looked into increasing the boat tail length? Or that no one in their employment knows about the Sears-Haack body?

You are claiming a bunch of BS then want people to buy your product to test it when you have given zero comparison data.

Also, drag is not the only input into a BC calculation, so show an actual BC calculation

You are doing this the wrong way, I'm done with this thread

 

[HappyHellfire]

Glad life worked out so well for you.
You have same the degree status as Dr. Jill Biden

Wow, that's a bit confrontational.

Jill Biden has a doctorate of education. I have a doctorate of philosophy in aerospace engineering. Not sure why that is offensive to you.

 

[Thauglor]

No sure what more data you want to see. The only real innovation that I am claiming is the aerospike base (inverted rocket nozzle). The data is pretty clear that it works.

No, there is no data that you have provided other than a drag curve which paints a positive picture of your "new" design but doesn't show the whole story

 

[HappyHellfire]

No, there is no data that you have provided other than a drag curve which paints a positive picture of your "new" design but doesn't show the whole story

What do you want to see? If I have it I'll share it.

 

[WSnyder]

No, there is no data that you have provided other than a drag curve which paints a positive picture of your "new" design but doesn't show the whole story

So rather than further the discussion by asking him questions we’re going to just dismiss the whole thing because he didn't post up the whole story upfront? Ridiculous.

Why not just chill and ask the man some questions? He seems reasonable enough and I'm sure he has lots to share if you ask.

 

[Thauglor]

View attachment 1565166

Look at the reduction in drag for the 6.5 Creedmoor/PRC design. I think I have solid ground to stand on here.

Copying this so we have proof for later. I will take your drag and calculate a bc at home tonight

 

[HappyHellfire]

Show your "calculated" BC comparison or even better show an actual fired doppler radar measured comparison. So we can all believe you, get Applied Ballistics, you know, the actual proven experts in the field, to measure it. They also don't go posting about their amazing phds to prove their point, take a hint from them

At this point my dog's shit has more credibility than you so even if you post speed results bot many will believe it due to your tactics here.

He is some of the radar data from a range date earlier this month. I use the radar data to calculate both the mach number and the drag coefficient.

Dia (m)

mass (grains)

range date

6/8/2024​

range (m)

0.0067​

101.5​

time

1200​

0​

10​

20​

30​

40​

50​

Shot #

Desired Mach

IMR 4895 (grains)

temp (K)

303.7056​

V0 (m/s)

V10

V20

V30

V40

V50

dv/dx

Mach

Cd

Mach

CD

1​

2.6​

37.0​

press (inHG)

29.96​

860​

851​

844​

837​

830​

822​

-0.74286​

2.397988​

0.284829​

average

2.381​

0.290​

2​

2.6​

37.0​

Humidity (%)

33​

849​

841​

834​

827​

820​

812​

-0.72857​

2.368987​

0.282771​

confidence

0.020​

0.005​

3​

2.6​

37.0​

density (kg/m^3)

1.1575​

857​

848​

841​

833​

826​

818​

-0.76857​

2.388004​

0.29592​

Mach

CD

4​

2.6​

37.0​

846​

838​

831​

824​

817​

809​

-0.72857​

2.36043​

0.283796​

average

2.573​

0.283​

5​

2.6​

37.0​

858​

850​

842​

835​

828​

820​

-0.75143​

2.392758​

0.288745​

confidence

0.013​

0.006​

6​

2.6​

37.0​

range date

6/9/2024​

842​

834​

826​

819​

812​

804​

-0.75143​

2.347118​

0.294359​

Mach

CD

7​

2.6​

37.0​

time

1444​

855​

847​

839​

832​

824​

816​

-0.77429​

2.38325​

0.298715​

average

2.138​

0.298​

8​

2.6​

37.0​

temp (K)

306.4833​

848​

840​

833​

826​

818​

811​

-0.73714​

2.365659​

0.2865​

confidence

0.012​

0.015​

9​

2.6​

37.0​

press (inHG)

29.88​

850​

843​

835​

828​

821​

813​

-0.73714​

2.372315​

0.285696​

Mach

CD

10​

2.6​

37.0​

Humidity (%)

47​

873​

864​

855​

848​

841​

833​

-0.78857​

2.431267​

0.298218​

average

1.783​

0.417​

11​

2.75​

39.7​

density (kg/m^3)

1.14023​

923​

915​

906​

899​

891​

884​

-0.78286​

2.564093​

0.283678​

confidence

0.034​

0.064​

12​

2.75​

39.7​

932​

923​

913​

906​

899​

891​

-0.81143​

2.585863​

0.291556​

Mach

CD

13​

2.75​

39.7​

929​

920​

910​

904​

896​

888​

-0.80857​

2.577818​

0.291436​

average

1.525​

0.422​

14​

2.75​

39.7​

927​

918​

910​

902​

895​

886​

-0.80571​

2.573558​

0.290887​

confidence

0.028​

0.061​

15​

2.75​

39.7​

930​

921​

912​

906​

899​

891​

-0.76286​

2.583497​

0.274354​

Mach

CD

16​

2.75​

39.7​

923​

914​

905​

899​

892​

884​

-0.76286​

2.56362​

0.276482​

average

1.263​

0.405​

17​

2.75​

39.7​

931​

922​

914​

907​

900​

891​

-0.78​

2.586336​

0.280212​

confidence

0.065​

0.074​

18​

2.75​

39.7​

916​

907​

899​

893​

885​

876​

-0.77714​

2.544217​

0.283807​

Mach

CD

19​

2.75​

39.7​

928​

919​

911​

904​

897​

889​

-0.76571​

2.578291​

0.275938​

average

0.905​

0.241​

20​

confidence

0.055​

0.045​

21​

2​

31.6​

773​

766​

759​

753​

746​

738​

-0.68857​

2.14621​

0.298094​

Mach

CD

22​

2​

31.6​

771​

764​

758​

752​

745​

738​

-0.65143​

2.142897​

0.28245​

average

#DIV/0!​

#DIV/0!​

23​

2​

31.6​

762​

753​

745​

739​

732​

-0.74​

2.118855​

0.324494​

confidence

#DIV/0!​

#DIV/0!​

24​

2​

31.6​

766​

759​

752​

746​

740​

733​

-0.65143​

2.127753​

0.284461​

Mach

CD

25​

2​

31.6​

773​

765​

758​

752​

744​

737​

-0.71143​

2.14337​

0.308397​

average

#DIV/0!​

#DIV/0!​

26​

2​

31.6​

778​

770​

763​

757​

750​

743​

-0.68857​

2.158514​

0.296395​

confidence

#DIV/0!​

#DIV/0!​

27​

2​

31.6​

773​

766​

759​

753​

746​

739​

-0.67429​

2.146683​

0.291845​

Mach

CD

28​

2​

31.6​

771​

761​

752​

746​

740​

732​

-0.75429​

2.130592​

0.328937​

average

#DIV/0!​

#DIV/0!​

29​

2​

31.6​

760​

753​

746​

741​

735​

728​

-0.62571​

2.112135​

0.275252​

confidence

#DIV/0!​

#DIV/0!​

30​

2​

31.6​

774​

766​

760​

754​

747​

740​

-0.66571​

2.149049​

0.287818​

31​

1.7​

26.4​

675​

667​

659​

651​

642​

633​

-0.83714​

1.858471​

0.418524​

32​

1.7​

26.4​

640​

633​

626​

619​

612​

606​

-0.68571​

1.768079​

0.360345​

33​

1.7​

26.4​

638​

630​

622​

615​

607​

600​

-0.76​

1.756721​

0.401964​

34​

1.7​

26.4​

641​

635​

629​

622​

617​

610​

-0.61714​

1.776598​

0.322755​

35​

1.7​

26.4​

639​

628​

618​

609​

600​

590​

-0.96571​

1.74347​

0.514649​

36​

1.7​

26.4​

642​

631​

621​

611​

602​

590​

-1.02​

1.749622​

0.541667​

37​

1.7​

26.4​

641​

632​

624​

616​

608​

599​

-0.82857​

1.760507​

0.437289​

38​

1.7​

26.4​

668​

660​

651​

642​

633​

623​

-0.9​

1.834808​

0.455752​

39​

1.7​

26.4​

663​

655​

645​

639​

631​

623​

-0.79429​

1.82487​

0.40441​

40​

1.7​

26.4​

635​

629​

623​

617​

611​

606​

-0.58571​

1.76098​

0.309035​

41​

1.5​

22.9​

553​

546​

539​

533​

526​

518​

-0.68857​

1.521514​

0.420484​

42​

1.5​

22.9​

558​

551​

543​

536​

529​

519​

-0.76571​

1.531452​

0.464558​

43​

1.5​

22.9​

571​

566​

560​

554​

549​

543​

-0.56286​

1.58209​

0.330555​

44​

1.5​

22.9​

557​

548​

539​

531​

522​

512​

-0.88857​

1.518674​

0.543631​

45​

1.5​

22.9​

534​

526​

518​

510​

502​

-0.8​

1.470875​

0.505348​

46​

1.5​

22.9​

546​

539​

532​

526​

-0.67​

1.521277​

0.409207​

47​

1.5​

22.9​

567​

562​

557​

551​

546​

540​

-0.54​

1.572625​

0.31904​

48​

1.5​

22.9​

543​

537​

531​

525​

519​

514​

-0.58571​

1.499744​

0.362865​

49​

1.5​

22.9​

546​

539​

532​

525​

518​

510​

-0.71429​

1.500217​

0.442379​

50​

1.5​

22.9​

556​

549​

542​

535​

528​

521​

-0.7​

1.529086​

0.425347​

51​

1.2​

17.6​

500​

495​

490​

485​

480​

476​

-0.48571​

1.384743​

0.325903​

52​

1.2​

17.6​

432​

427​

423​

418​

414​

409​

-0.45429​

1.194021​

0.353503​

53​

1.2​

17.6​

438​

431​

424​

417​

412​

410​

-0.58286​

1.198281​

0.451939​

54​

1.2​

17.6​

493​

487​

482​

476​

470​

465​

-0.56286​

1.35966​

0.384631​

55​

1.2​

17.6​

422​

417​

411​

406​

402​

397​

-0.5​

1.16184​

0.399853​

56​

1.2​

17.6​

448​

438​

429​

423​

414​

407​

-0.80857​

1.211059​

0.62034​

57​

1.2​

17.6​

473​

467​

461​

455​

449​

442​

-0.61429​

1.30003​

0.439029​

58​

1.2​

17.6​

468​

463​

459​

454​

448​

445​

-0.47143​

1.295298​

0.338161​

59​

1.2​

17.6​

471​

466​

462​

457​

452​

447​

-0.47714​

1.303816​

0.340023​

60​

1.2​

17.6​

442​

437​

432​

427​

422​

416​

-0.51429​

1.219104​

0.391959​

61​

0.9​

12.4​

353​

350​

346​

343​

340​

338​

-0.30857​

0.979637​

0.292663​

62​

0.9​

12.4​

325​

322​

319​

317​

315​

312​

-0.25143​

0.903916​

0.258442​

63​

0.9​

12.4​

316​

315​

313​

311​

309​

307​

-0.18571​

0.885459​

0.194874​

64​

0.9​

12.4​

349​

345​

341​

338​

335​

330​

-0.36571​

0.964493​

0.352306​

65​

0.9​

12.4​

318​

316​

313​

311​

309​

306​

-0.23714​

0.886406​

0.248573​

66​

0.9​

12.4​

281​

280​

278​

277​

275​

273​

-0.16​

0.787496​

0.188777​

67​

0.9​

12.4​

292​

290​

288​

287​

286​

283​

-0.16571​

0.816837​

0.188496​

68​

0.9​

12.4​

338​

336​

333​

331​

328​

326​

-0.24571​

0.942723​

0.242171​

69​

0.9​

12.4​

325​

323​

321​

320​

318​

315​

-0.18857​

0.909595​

0.192621​

70​

0.9​

12.4​

347​

344​

341​

339​

337​

333​

-0.26571​

0.969983​

0.254523​

 

[HappyHellfire]

He is some of the radar data from a range date earlier this month. I use the radar data to calculate both the mach number and the drag coefficient.

Dia (m)

mass (grains)

range date

6/8/2024​

range (m)

0.0067​

101.5​

time

1200​

0​

10​

20​

30​

40​

50​

Shot #

Desired Mach

IMR 4895 (grains)

temp (K)

303.7056​

V0 (m/s)

V10

V20

V30

V40

V50

dv/dx

Mach

Cd

Mach

CD

1​

2.6​

37.0​

press (inHG)

29.96​

860​

851​

844​

837​

830​

822​

-0.74286​

2.397988​

0.284829​

average

2.381​

0.290​

2​

2.6​

37.0​

Humidity (%)

33​

849​

841​

834​

827​

820​

812​

-0.72857​

2.368987​

0.282771​

confidence

0.020​

0.005​

3​

2.6​

37.0​

density (kg/m^3)

1.1575​

857​

848​

841​

833​

826​

818​

-0.76857​

2.388004​

0.29592​

Mach

CD

4​

2.6​

37.0​

846​

838​

831​

824​

817​

809​

-0.72857​

2.36043​

0.283796​

average

2.573​

0.283​

5​

2.6​

37.0​

858​

850​

842​

835​

828​

820​

-0.75143​

2.392758​

0.288745​

confidence

0.013​

0.006​

6​

2.6​

37.0​

range date

6/9/2024​

842​

834​

826​

819​

812​

804​

-0.75143​

2.347118​

0.294359​

Mach

CD

7​

2.6​

37.0​

time

1444​

855​

847​

839​

832​

824​

816​

-0.77429​

2.38325​

0.298715​

average

2.138​

0.298​

8​

2.6​

37.0​

temp (K)

306.4833​

848​

840​

833​

826​

818​

811​

-0.73714​

2.365659​

0.2865​

confidence

0.012​

0.015​

9​

2.6​

37.0​

press (inHG)

29.88​

850​

843​

835​

828​

821​

813​

-0.73714​

2.372315​

0.285696​

Mach

CD

10​

2.6​

37.0​

Humidity (%)

47​

873​

864​

855​

848​

841​

833​

-0.78857​

2.431267​

0.298218​

average

1.783​

0.417​

11​

2.75​

39.7​

density (kg/m^3)

1.14023​

923​

915​

906​

899​

891​

884​

-0.78286​

2.564093​

0.283678​

confidence

0.034​

0.064​

12​

2.75​

39.7​

932​

923​

913​

906​

899​

891​

-0.81143​

2.585863​

0.291556​

Mach

CD

13​

2.75​

39.7​

929​

920​

910​

904​

896​

888​

-0.80857​

2.577818​

0.291436​

average

1.525​

0.422​

14​

2.75​

39.7​

927​

918​

910​

902​

895​

886​

-0.80571​

2.573558​

0.290887​

confidence

0.028​

0.061​

15​

2.75​

39.7​

930​

921​

912​

906​

899​

891​

-0.76286​

2.583497​

0.274354​

Mach

CD

16​

2.75​

39.7​

923​

914​

905​

899​

892​

884​

-0.76286​

2.56362​

0.276482​

average

1.263​

0.405​

17​

2.75​

39.7​

931​

922​

914​

907​

900​

891​

-0.78​

2.586336​

0.280212​

confidence

0.065​

0.074​

18​

2.75​

39.7​

916​

907​

899​

893​

885​

876​

-0.77714​

2.544217​

0.283807​

Mach

CD

19​

2.75​

39.7​

928​

919​

911​

904​

897​

889​

-0.76571​

2.578291​

0.275938​

average

0.905​

0.241​

20​

confidence

0.055​

0.045​

21​

2​

31.6​

773​

766​

759​

753​

746​

738​

-0.68857​

2.14621​

0.298094​

Mach

CD

22​

2​

31.6​

771​

764​

758​

752​

745​

738​

-0.65143​

2.142897​

0.28245​

average

#DIV/0!​

#DIV/0!​

23​

2​

31.6​

762​

753​

745​

739​

732​

-0.74​

2.118855​

0.324494​

confidence

#DIV/0!​

#DIV/0!​

24​

2​

31.6​

766​

759​

752​

746​

740​

733​

-0.65143​

2.127753​

0.284461​

Mach

CD

25​

2​

31.6​

773​

765​

758​

752​

744​

737​

-0.71143​

2.14337​

0.308397​

average

#DIV/0!​

#DIV/0!​

26​

2​

31.6​

778​

770​

763​

757​

750​

743​

-0.68857​

2.158514​

0.296395​

confidence

#DIV/0!​

#DIV/0!​

27​

2​

31.6​

773​

766​

759​

753​

746​

739​

-0.67429​

2.146683​

0.291845​

Mach

CD

28​

2​

31.6​

771​

761​

752​

746​

740​

732​

-0.75429​

2.130592​

0.328937​

average

#DIV/0!​

#DIV/0!​

29​

2​

31.6​

760​

753​

746​

741​

735​

728​

-0.62571​

2.112135​

0.275252​

confidence

#DIV/0!​

#DIV/0!​

30​

2​

31.6​

774​

766​

760​

754​

747​

740​

-0.66571​

2.149049​

0.287818​

31​

1.7​

26.4​

675​

667​

659​

651​

642​

633​

-0.83714​

1.858471​

0.418524​

32​

1.7​

26.4​

640​

633​

626​

619​

612​

606​

-0.68571​

1.768079​

0.360345​

33​

1.7​

26.4​

638​

630​

622​

615​

607​

600​

-0.76​

1.756721​

0.401964​

34​

1.7​

26.4​

641​

635​

629​

622​

617​

610​

-0.61714​

1.776598​

0.322755​

35​

1.7​

26.4​

639​

628​

618​

609​

600​

590​

-0.96571​

1.74347​

0.514649​

36​

1.7​

26.4​

642​

631​

621​

611​

602​

590​

-1.02​

1.749622​

0.541667​

37​

1.7​

26.4​

641​

632​

624​

616​

608​

599​

-0.82857​

1.760507​

0.437289​

38​

1.7​

26.4​

668​

660​

651​

642​

633​

623​

-0.9​

1.834808​

0.455752​

39​

1.7​

26.4​

663​

655​

645​

639​

631​

623​

-0.79429​

1.82487​

0.40441​

40​

1.7​

26.4​

635​

629​

623​

617​

611​

606​

-0.58571​

1.76098​

0.309035​

41​

1.5​

22.9​

553​

546​

539​

533​

526​

518​

-0.68857​

1.521514​

0.420484​

42​

1.5​

22.9​

558​

551​

543​

536​

529​

519​

-0.76571​

1.531452​

0.464558​

43​

1.5​

22.9​

571​

566​

560​

554​

549​

543​

-0.56286​

1.58209​

0.330555​

44​

1.5​

22.9​

557​

548​

539​

531​

522​

512​

-0.88857​

1.518674​

0.543631​

45​

1.5​

22.9​

534​

526​

518​

510​

502​

-0.8​

1.470875​

0.505348​

46​

1.5​

22.9​

546​

539​

532​

526​

-0.67​

1.521277​

0.409207​

47​

1.5​

22.9​

567​

562​

557​

551​

546​

540​

-0.54​

1.572625​

0.31904​

48​

1.5​

22.9​

543​

537​

531​

525​

519​

514​

-0.58571​

1.499744​

0.362865​

49​

1.5​

22.9​

546​

539​

532​

525​

518​

510​

-0.71429​

1.500217​

0.442379​

50​

1.5​

22.9​

556​

549​

542​

535​

528​

521​

-0.7​

1.529086​

0.425347​

51​

1.2​

17.6​

500​

495​

490​

485​

480​

476​

-0.48571​

1.384743​

0.325903​

52​

1.2​

17.6​

432​

427​

423​

418​

414​

409​

-0.45429​

1.194021​

0.353503​

53​

1.2​

17.6​

438​

431​

424​

417​

412​

410​

-0.58286​

1.198281​

0.451939​

54​

1.2​

17.6​

493​

487​

482​

476​

470​

465​

-0.56286​

1.35966​

0.384631​

55​

1.2​

17.6​

422​

417​

411​

406​

402​

397​

-0.5​

1.16184​

0.399853​

56​

1.2​

17.6​

448​

438​

429​

423​

414​

407​

-0.80857​

1.211059​

0.62034​

57​

1.2​

17.6​

473​

467​

461​

455​

449​

442​

-0.61429​

1.30003​

0.439029​

58​

1.2​

17.6​

468​

463​

459​

454​

448​

445​

-0.47143​

1.295298​

0.338161​

59​

1.2​

17.6​

471​

466​

462​

457​

452​

447​

-0.47714​

1.303816​

0.340023​

60​

1.2​

17.6​

442​

437​

432​

427​

422​

416​

-0.51429​

1.219104​

0.391959​

61​

0.9​

12.4​

353​

350​

346​

343​

340​

338​

-0.30857​

0.979637​

0.292663​

62​

0.9​

12.4​

325​

322​

319​

317​

315​

312​

-0.25143​

0.903916​

0.258442​

63​

0.9​

12.4​

316​

315​

313​

311​

309​

307​

-0.18571​

0.885459​

0.194874​

64​

0.9​

12.4​

349​

345​

341​

338​

335​

330​

-0.36571​

0.964493​

0.352306​

65​

0.9​

12.4​

318​

316​

313​

311​

309​

306​

-0.23714​

0.886406​

0.248573​

66​

0.9​

12.4​

281​

280​

278​

277​

275​

273​

-0.16​

0.787496​

0.188777​

67​

0.9​

12.4​

292​

290​

288​

287​

286​

283​

-0.16571​

0.816837​

0.188496​

68​

0.9​

12.4​

338​

336​

333​

331​

328​

326​

-0.24571​

0.942723​

0.242171​

69​

0.9​

12.4​

325​

323​

321​

320​

318​

315​

-0.18857​

0.909595​

0.192621​

70​

0.9​

12.4​

347​

344​

341​

339​

337​

333​

-0.26571​

0.969983​

0.254523​

Like we used to say at Dahlgren, "In God we trust but all others bring data".

 

[Thauglor]

He is some of the radar data from a range date earlier this month. I use the radar data to calculate both the mach number and the drag coefficient.

Dia (m)

mass (grains)

range date

6/8/2024​

range (m)

0.0067​

101.5​

time

1200​

0​

10​

20​

30​

40​

50​

Shot #

Desired Mach

IMR 4895 (grains)

temp (K)

303.7056​

V0 (m/s)

V10

V20

V30

V40

V50

dv/dx

Mach

Cd

Mach

CD

1​

2.6​

37.0​

press (inHG)

29.96​

860​

851​

844​

837​

830​

822​

-0.74286​

2.397988​

0.284829​

average

2.381​

0.290​

2​

2.6​

37.0​

Humidity (%)

33​

849​

841​

834​

827​

820​

812​

-0.72857​

2.368987​

0.282771​

confidence

0.020​

0.005​

3​

2.6​

37.0​

density (kg/m^3)

1.1575​

857​

848​

841​

833​

826​

818​

-0.76857​

2.388004​

0.29592​

Mach

CD

4​

2.6​

37.0​

846​

838​

831​

824​

817​

809​

-0.72857​

2.36043​

0.283796​

average

2.573​

0.283​

5​

2.6​

37.0​

858​

850​

842​

835​

828​

820​

-0.75143​

2.392758​

0.288745​

confidence

0.013​

0.006​

6​

2.6​

37.0​

range date

6/9/2024​

842​

834​

826​

819​

812​

804​

-0.75143​

2.347118​

0.294359​

Mach

CD

7​

2.6​

37.0​

time

1444​

855​

847​

839​

832​

824​

816​

-0.77429​

2.38325​

0.298715​

average

2.138​

0.298​

8​

2.6​

37.0​

temp (K)

306.4833​

848​

840​

833​

826​

818​

811​

-0.73714​

2.365659​

0.2865​

confidence

0.012​

0.015​

9​

2.6​

37.0​

press (inHG)

29.88​

850​

843​

835​

828​

821​

813​

-0.73714​

2.372315​

0.285696​

Mach

CD

10​

2.6​

37.0​

Humidity (%)

47​

873​

864​

855​

848​

841​

833​

-0.78857​

2.431267​

0.298218​

average

1.783​

0.417​

11​

2.75​

39.7​

density (kg/m^3)

1.14023​

923​

915​

906​

899​

891​

884​

-0.78286​

2.564093​

0.283678​

confidence

0.034​

0.064​

12​

2.75​

39.7​

932​

923​

913​

906​

899​

891​

-0.81143​

2.585863​

0.291556​

Mach

CD

13​

2.75​

39.7​

929​

920​

910​

904​

896​

888​

-0.80857​

2.577818​

0.291436​

average

1.525​

0.422​

14​

2.75​

39.7​

927​

918​

910​

902​

895​

886​

-0.80571​

2.573558​

0.290887​

confidence

0.028​

0.061​

15​

2.75​

39.7​

930​

921​

912​

906​

899​

891​

-0.76286​

2.583497​

0.274354​

Mach

CD

16​

2.75​

39.7​

923​

914​

905​

899​

892​

884​

-0.76286​

2.56362​

0.276482​

average

1.263​

0.405​

17​

2.75​

39.7​

931​

922​

914​

907​

900​

891​

-0.78​

2.586336​

0.280212​

confidence

0.065​

0.074​

18​

2.75​

39.7​

916​

907​

899​

893​

885​

876​

-0.77714​

2.544217​

0.283807​

Mach

CD

19​

2.75​

39.7​

928​

919​

911​

904​

897​

889​

-0.76571​

2.578291​

0.275938​

average

0.905​

0.241​

20​

confidence

0.055​

0.045​

21​

2​

31.6​

773​

766​

759​

753​

746​

738​

-0.68857​

2.14621​

0.298094​

Mach

CD

22​

2​

31.6​

771​

764​

758​

752​

745​

738​

-0.65143​

2.142897​

0.28245​

average

#DIV/0!​

#DIV/0!​

23​

2​

31.6​

762​

753​

745​

739​

732​

-0.74​

2.118855​

0.324494​

confidence

#DIV/0!​

#DIV/0!​

24​

2​

31.6​

766​

759​

752​

746​

740​

733​

-0.65143​

2.127753​

0.284461​

Mach

CD

25​

2​

31.6​

773​

765​

758​

752​

744​

737​

-0.71143​

2.14337​

0.308397​

average

#DIV/0!​

#DIV/0!​

26​

2​

31.6​

778​

770​

763​

757​

750​

743​

-0.68857​

2.158514​

0.296395​

confidence

#DIV/0!​

#DIV/0!​

27​

2​

31.6​

773​

766​

759​

753​

746​

739​

-0.67429​

2.146683​

0.291845​

Mach

CD

28​

2​

31.6​

771​

761​

752​

746​

740​

732​

-0.75429​

2.130592​

0.328937​

average

#DIV/0!​

#DIV/0!​

29​

2​

31.6​

760​

753​

746​

741​

735​

728​

-0.62571​

2.112135​

0.275252​

confidence

#DIV/0!​

#DIV/0!​

30​

2​

31.6​

774​

766​

760​

754​

747​

740​

-0.66571​

2.149049​

0.287818​

31​

1.7​

26.4​

675​

667​

659​

651​

642​

633​

-0.83714​

1.858471​

0.418524​

32​

1.7​

26.4​

640​

633​

626​

619​

612​

606​

-0.68571​

1.768079​

0.360345​

33​

1.7​

26.4​

638​

630​

622​

615​

607​

600​

-0.76​

1.756721​

0.401964​

34​

1.7​

26.4​

641​

635​

629​

622​

617​

610​

-0.61714​

1.776598​

0.322755​

35​

1.7​

26.4​

639​

628​

618​

609​

600​

590​

-0.96571​

1.74347​

0.514649​

36​

1.7​

26.4​

642​

631​

621​

611​

602​

590​

-1.02​

1.749622​

0.541667​

37​

1.7​

26.4​

641​

632​

624​

616​

608​

599​

-0.82857​

1.760507​

0.437289​

38​

1.7​

26.4​

668​

660​

651​

642​

633​

623​

-0.9​

1.834808​

0.455752​

39​

1.7​

26.4​

663​

655​

645​

639​

631​

623​

-0.79429​

1.82487​

0.40441​

40​

1.7​

26.4​

635​

629​

623​

617​

611​

606​

-0.58571​

1.76098​

0.309035​

41​

1.5​

22.9​

553​

546​

539​

533​

526​

518​

-0.68857​

1.521514​

0.420484​

42​

1.5​

22.9​

558​

551​

543​

536​

529​

519​

-0.76571​

1.531452​

0.464558​

43​

1.5​

22.9​

571​

566​

560​

554​

549​

543​

-0.56286​

1.58209​

0.330555​

44​

1.5​

22.9​

557​

548​

539​

531​

522​

512​

-0.88857​

1.518674​

0.543631​

45​

1.5​

22.9​

534​

526​

518​

510​

502​

-0.8​

1.470875​

0.505348​

46​

1.5​

22.9​

546​

539​

532​

526​

-0.67​

1.521277​

0.409207​

47​

1.5​

22.9​

567​

562​

557​

551​

546​

540​

-0.54​

1.572625​

0.31904​

48​

1.5​

22.9​

543​

537​

531​

525​

519​

514​

-0.58571​

1.499744​

0.362865​

49​

1.5​

22.9​

546​

539​

532​

525​

518​

510​

-0.71429​

1.500217​

0.442379​

50​

1.5​

22.9​

556​

549​

542​

535​

528​

521​

-0.7​

1.529086​

0.425347​

51​

1.2​

17.6​

500​

495​

490​

485​

480​

476​

-0.48571​

1.384743​

0.325903​

52​

1.2​

17.6​

432​

427​

423​

418​

414​

409​

-0.45429​

1.194021​

0.353503​

53​

1.2​

17.6​

438​

431​

424​

417​

412​

410​

-0.58286​

1.198281​

0.451939​

54​

1.2​

17.6​

493​

487​

482​

476​

470​

465​

-0.56286​

1.35966​

0.384631​

55​

1.2​

17.6​

422​

417​

411​

406​

402​

397​

-0.5​

1.16184​

0.399853​

56​

1.2​

17.6​

448​

438​

429​

423​

414​

407​

-0.80857​

1.211059​

0.62034​

57​

1.2​

17.6​

473​

467​

461​

455​

449​

442​

-0.61429​

1.30003​

0.439029​

58​

1.2​

17.6​

468​

463​

459​

454​

448​

445​

-0.47143​

1.295298​

0.338161​

59​

1.2​

17.6​

471​

466​

462​

457​

452​

447​

-0.47714​

1.303816​

0.340023​

60​

1.2​

17.6​

442​

437​

432​

427​

422​

416​

-0.51429​

1.219104​

0.391959​

61​

0.9​

12.4​

353​

350​

346​

343​

340​

338​

-0.30857​

0.979637​

0.292663​

62​

0.9​

12.4​

325​

322​

319​

317​

315​

312​

-0.25143​

0.903916​

0.258442​

63​

0.9​

12.4​

316​

315​

313​

311​

309​

307​

-0.18571​

0.885459​

0.194874​

64​

0.9​

12.4​

349​

345​

341​

338​

335​

330​

-0.36571​

0.964493​

0.352306​

65​

0.9​

12.4​

318​

316​

313​

311​

309​

306​

-0.23714​

0.886406​

0.248573​

66​

0.9​

12.4​

281​

280​

278​

277​

275​

273​

-0.16​

0.787496​

0.188777​

67​

0.9​

12.4​

292​

290​

288​

287​

286​

283​

-0.16571​

0.816837​

0.188496​

68​

0.9​

12.4​

338​

336​

333​

331​

328​

326​

-0.24571​

0.942723​

0.242171​

69​

0.9​

12.4​

325​

323​

321​

320​

318​

315​

-0.18857​

0.909595​

0.192621​

70​

0.9​

12.4​

347​

344​

341​

339​

337​

333​

-0.26571​

0.969983​

0.254523​

If you are saying this is for your bullet, then this doesn't even match your plot. A cd of 0.422 at mach 1.525 is worse than the sierra 168 gr you have plotted

 

[HappyHellfire]

Again what you posted is not data, its just a tabular form of your little plot you showed already. Presenting the same data in a different format and calling it something new is fraud in science papers

If you are saying this is for your bullet, then this doesn't even match your plot. A cd of 0.422 at mach 1.525 is worse than the sierra 168 gr you have plotted

You're really good at data analysis! Yes, this data is where I discovered that the rounds started to get marginally stable below Mach 2.2.

 

[Thauglor]

You're really good at data analysis! Yes, this data is where I discovered that the rounds started to get marginally stable below Mach 2.2.

But no response as to why your data is showing a cd of above 0.4 at mach 1.5 when your plot clearly shows around 0.325?

Are you throwing away data here?

 

[HappyHellfire]

But no response as to why your data is showing a cd of above 0.4 at mach 1.5 when your plot clearly shows around 0.325?

Are you throwing away data here?

Sorry, I thought I was being clear. When the bullet becomes marginally stable it's epicyclic motion (the wobble while flying) increases and the drag increases. If you plot the data, you will see that above Mach 2.2 the rounds are tightly grouped but below that the data spreads out vertically. This is a clear sign of losing stability.

 

[HappyHellfire]

Maybe we should start another thread on projectile testing?

 

[Thauglor]

Sorry, I thought I was being clear. When the bullet becomes marginally stable it's epicyclic motion (the wobble while flying) increases and the drag increases. If you plot the data, you will see that above Mach 2.2 the rounds are tightly grouped but below that the data spreads out vertically. This is a clear sign of losing stability.

So then why does your plot for mach 1.5 to say 0.325ish cd instead of your data that says 0.422ish? Smells like fraud to me

Edit to add: you have a whole region of cd above 0.4 from mach 1.2 to 1.7, yet your plot never goes above 0.35. Explain that

 

[HappyHellfire]

So then how did you get the data in your plot for mach 1.5 to say 0.325ish cd instead of your data that says 0.422ish? Smells like fraud to me

You are comparing a 140 grain bullet to a 102 grain bullet.

 

[HappyHellfire]

So then why does your plot for mach 1.5 to say 0.325ish cd instead of your data that says 0.422ish? Smells like fraud to me

Edit to add: you have a whole region of cd above 0.4 from mach 1.2 to 1.7, yet your plot never goes above 0.35. Explain that

The drag curve is a combination of hundreds of test firings. The lower Mach number data was collected on another day. You just wanted to see data so I pulled up one of my recent tests.

You seem really interested and that is cool. I am putting together a journal paper for Defense Technology published by the International Ballistics Society that I plan to present at the next meeting in May. It will have the level of detail that you are requesting.