Software challenge

12 October 2003, 03:10

Sabot

Software challenge

I am boneheaded enough to think that my PERSONAL internal ballistics program is better than any of the commercial software out there. It runs in EXCEL and is less than 1/10th the size of any of the competition.

Don't you just hate overconfident braggers? Me too...I am hating myself, so I need to be proven wrong so I can fell good again. So, please send me the following information for a rifle application:

1. Case capacity in grs of water...please specify as max or usable.
2. Bullet diameter and weight in grains.
3. Pressure max for the rifle in CUP or PSI.

That's it! I will tell you the maximum potential velocity with the given bullet, the barrel length it will take to achieve that velocity and a powder to work up.

Make me wong, I will feel better!

12 October 2003, 17:43

Turok

I'll bite.

338WM

WW Case - 77.7 gr water (max)
.338 Dia. 225gr bullet
65,000 PSI

Turok

[ 10-12-2003, 08:43: Message edited by: Turok ]

12 October 2003, 17:48

Turok

I'll raise the bar a little bit, I have pressure testing equipment to see how accurate your software is.

Turok

13 October 2003, 03:25

Sabot

TUROK -

Thanks, this is fun.

For your 338 example I have:

225 gr bullet = 2897 fps and 4199 FPE

Recoil = 38.8 FP in an 8 .5 lb rifle

Barrel needs to be 24.26 inches long.

Powder burn rate is 42.6, close to R19.

13 October 2003, 03:38

Turok

quote:
Originally posted by Sabot:

Recoil = 38.8 FP in an 8 .5 lb rifle

I believe it's EVERY bit of that!

I've shot R19 out of my rifle before, but I hadn't chronographed it. Unfortunately my chrony does't work unless it is pretty cloudy. I'll have to pick up another pound and see if I can get out pretty soon. [Smile]

Turok

14 October 2003, 05:16

Turok

I haven't been able to get to the gunshop for any R19 yet, but I do have data from Alliant. They list R19 @ 75.3, WLR Primer, 2865 fps with a 24" Bbl when run to 52,100 CUP.

Pretty close to what your software predicted.

Turok

15 October 2003, 03:14

Sabot

Turok -

Thanks...that is PRETTY close!!

How about another test?

15 October 2003, 19:23

Turok

I agree. That is pretty close. I'll get you to run it with my buddies .308 Norma when I get the chance. I'm in the middle of midterms right now.

Turok

16 October 2003, 09:32

Brent Moffitt

30/338 Lapua Imp 40 deg, 117gr water full to the top, 200gr Accubond at 3.750" OAL at 65,000 psi. in a 30.5" bbl.

Same, but with a 178gr A-Max at 3.700" OAL

Same, but with a 210gr JLK at 3.750" OAL

300 Ultra Mag, 114gr water to the top, 200gr accubond at 3.830" OAL 65 kpsi in a 26" bbl.

Same, but with the 178gr A-Max at 3.660" OAL

I have pressure data from the Oehler 43 and PressureTrace on some of these loads, be neat to compare them.

16 October 2003, 02:39

Sabot

Brent -

Great set of problems!! Can you provide me with the seating depths? Just need to calc the amount of powder displaced. The following is based on an assumed 0.40 inch seating depth for just the 200 gr accubond:

Velocity: 3302 fps

Energy: 4850 fpe

Recoil: 41.9 FP (10 lb rifle).

Burn Rate: 28.25 (close to AA8700)

PS...your long barrel really helps this round!

16 October 2003, 09:47

Brent Moffitt

Sabot,

Check these loads here if you would. I know I have some data on them.

Seating depth are as follows:

.425" 30-338 LI 200 AB at 3.750"
.275" 30-338 LI 178 AMX at 3.702"

.350" 300 Ultra 178 AMX at 3.760"
.475" 300 Ultra 200 AB at 3.835"

Which case was that MV there figured on, the Ultra or the Lapua?

RL25 and Retumbo are all I use in these.

16 October 2003, 10:28

Pecos41

Sabot - So is your personal program for sale or what?

16 October 2003, 17:33

Vibe

"1. Case capacity in grs of water...please specify as max or usable."

4.3 max

2. Bullet diameter and weight in grains.

0.223 @ 35, 40, 45, and 50

3. Pressure max for the rifle in CUP or PSI

30,000 PSI

Many load programs just do not do small cases well, or at all.

16 October 2003, 18:10

Lar45

Okay, I've got one for you.

73gn usable water capacity.
.703" bore
1oz slug
6.5" barrel
8-10kpsi max.

[ 10-16-2003, 09:14: Message edited by: Lar45 ]

17 October 2003, 04:39

Gustavo

Sabot,

Would you be glad enough to post your formulas or spreadsheet in order to use it ?

Tks in advance!

17 October 2003, 06:52

Sabot

BRENT -

The above calc was for the Lapua case. How'd I do?

I will do the others tonight.

Pecos and Gustavo -

Don't know what to do with it yet. First i need to see if it works on a wide variety of applications. [Wink]

17 October 2003, 06:55

Gustavo

quote:
Originally posted by Sabot:
BRENT -

The above calc was for the Lapua case. How'd I do?

I will do the others tonight.

Pecos and Gustavo -

Don't know what to do with it yet. First i need to see if it works on a wide variety of applications.

I understand your position, my idea was, if you provided us with the tool, we can do further research, sort of beta testers (a common practice in the software industry)

Tks anyway!

17 October 2003, 07:12

Sabot

VIBE -

Just had to try yours with 35 gr bullet for starters:

Velocity: 1642 fps

Energy 210 FP

Recoil in 10 lb rifle: .195 FP

Bbl length: 13.71

Powder burn rate: 186!!

Problem is a powder this fast that is still quite dense. Best guess is Bullseye or compressed flake in the Universal to Red Dot range. Might have to drop to 1200 to 1300 fps if Bullseye is too hot.

17 October 2003, 07:24

Sabot

LAR 45 -

Well, yours is a pistol, and I have no expectations that this model will work in a 6.5 inch bbl, but here goes:

Velocity for 450 gr bullet: 1060 fps

Energy: 1124 FP

Recoil: 47 FP in a 5 lb pistol (OUCH!)

Powder rate: 78.6 in the Blue Dot to Longshot range. Hey is this a cut off 12 GA? [Razz]

17 October 2003, 07:27

Sabot

quote:
Originally posted by Sabot:
LAR 45 -

Well, yours is a pistol, and I have no expectations that this model will work in a 6.5 inch bbl, but here goes:

Velocity for 450 gr bullet: 1060 fps

Energy: 1124 FP

Recoil: 47 FP in a 5 lb pistol (OUCH!)

PS the model wants a 14 inch bbl, but it only gives you an extra 100 fps over the 6.5 incher.

Powder rate: 78.6 in the Blue Dot to Longshot range. Hey is this a cut off 12 GA?

[ 10-16-2003, 22:29: Message edited by: Sabot ]

18 October 2003, 08:59

Lar45

No it's a pinfire Howda. Original Belgian double pistol. It only weighs in at 2lb 3oz. Does your program give a powder charge? Does it do Black powder? Anybody know what black powder pressures run?

[ 10-18-2003, 06:23: Message edited by: Lar45 ]

18 October 2003, 16:20

Vibe

In reality 231 performed better at 1850fps than Bullseye did with the 35gr load. You numbers are close to the Bulleye performance, but 231 may be going beyond the posted pressure level, though still within the capability of the case - no loose primers or case expansion.

Bulleye DID outperform the other powders with the 45 grain bullets though and achieved 1600fps. Both tests were from a 22" 22LR bore barrel.

quote:
Originally posted by Sabot:
VIBE -

Just had to try yours with 35 gr bullet for starters:

Velocity: 1642 fps

Energy 210 FP

Recoil in 10 lb rifle: .195 FP

Bbl length: 13.71

Powder burn rate: 186!!

Problem is a powder this fast that is still quite dense. Best guess is Bullseye or compressed flake in the Universal to Red Dot range. Might have to drop to 1200 to 1300 fps if Bullseye is too hot.

[ 10-18-2003, 07:24: Message edited by: Vibe ]

19 October 2003, 04:17

Sabot

Vibe -

Frankly, i am very surprised I even came close in such an unusual application. Thanks for the test data.

Lar 45 -

I don't dare give a starting charge because the model is for rifles and you have over 3 times the case capacity you need. Its fairly close to a 12 ga, so you could look up some 1 OZ light 12 ga loads, but you will definitely need wads.

I believe there is also good black powder data out there for 12 ga shotguns...you could look that over.

26 October 2003, 11:48

Vibe

I figured the best way to ask this question was to drag this thread back to the top.

Sabot you refered to a burn rate numbers. Where do you find those? Do you have very many powders catigorized by burn rate number? And could you post that list?

27 October 2003, 05:52

Sabot

Vibe -

Burn rate numbers are one of the things that my model calculates in place of taking a specific powder as an input (independent variable). In this manner, the model first calculates the maximum energy and velocity the case and barrel can deliver, given the rignt powder, and then tells you the burn rate using a metric that I scaled to highway speed limits. So, 55 to 65 is middle of the road and 20 to 25 is about as slow as you can go.

To get this number divide the usable case capacity in grs water by the bore squared and divide this number into ten times the velocity of the bullet at muzzle .I am still matching up powders with burn rates, but so far they make very good sense.