Ever wonder if the software is helpful?
Here is a bit of data I generated for Waco and his 308 long range pursuits.
This is a table showing small changes in powder with a single bullet and OAL. This shows 80 to 110 percent of case capacity.
This is just a bit of the data the program can generate. I find that for rifles the predicted velocities are pretty close to the chronograph.
Cartridge : .308 Win. (SAAMI)
Bullet : .31, 165, NOE 310-165-FN(GC) XCB
Useable Case Capaci: 52.474 grain H2O = 3.407 cm³
Cartridge O.A.L. L6: 2.760 inch = 70.10 mm
Barrel Length : 20.0 inch = 508.0 mm
Powder : Alliant Reloder-17
Predicted data by increasing and decreasing the given charge,
incremented in steps of 2.0% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !
Step Fill. Charge Vel. Energy Pmax Pmuz Prop.Burnt B_Time
% % Grains fps ft.lbs psi psi % ms
-20.0 81 40.93 2006 1474 22423 7985 81.8 1.546
-18.0 83 41.95 2067 1565 24090 8338 83.8 1.492
-16.0 85 42.97 2128 1659 25877 8683 85.7 1.441
-14.0 87 44.00 2190 1757 27792 9019 87.6 1.392
-12.0 89 45.02 2252 1858 29845 9343 89.3 1.345
-10.0 91 46.04 2314 1962 32049 9653 90.9 1.300
-08.0 93 47.07 2377 2069 34415 9949 92.4 1.256
-06.0 95 48.09 2439 2180 36959 10228 93.7 1.214
-04.0 97 49.11 2502 2293 39697 10489 95.0 1.174
-02.0 99 50.14 2565 2410 42646 10730 96.1 1.135
+00.0 101 51.16 2627 2529 45826 10950 97.0 1.098
+02.0 103 52.18 2690 2651 49262 11147 97.9 1.062
+04.0 105 53.21 2752 2775 52975 11320 98.6 1.028 ! Near Maximum !
+06.0 107 54.23 2814 2902 56998 11467 99.1 0.995 ! Near Maximum !
+08.0 109 55.25 2876 3031 61363 11588 99.6 0.962 !DANGEROUS LOAD-DO NOT USE!
+10.0 111 56.28 2938 3162 66105 11680 99.8 0.932 !DANGEROUS LOAD-DO NOT USE!
Results caused by ± 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba 101 51.16 2792 2857 56244 10801 100.0 1.004 ! Near Maximum !
Data for burning rate decreased by 10% relative to nominal value:
-Ba 101 51.16 2406 2121 36783 10248 87.9 1.220
Here is a bit of data I generated for Waco and his 308 long range pursuits.
This is a table showing small changes in powder with a single bullet and OAL. This shows 80 to 110 percent of case capacity.
This is just a bit of the data the program can generate. I find that for rifles the predicted velocities are pretty close to the chronograph.
Cartridge : .308 Win. (SAAMI)
Bullet : .31, 165, NOE 310-165-FN(GC) XCB
Useable Case Capaci: 52.474 grain H2O = 3.407 cm³
Cartridge O.A.L. L6: 2.760 inch = 70.10 mm
Barrel Length : 20.0 inch = 508.0 mm
Powder : Alliant Reloder-17
Predicted data by increasing and decreasing the given charge,
incremented in steps of 2.0% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !
Step Fill. Charge Vel. Energy Pmax Pmuz Prop.Burnt B_Time
% % Grains fps ft.lbs psi psi % ms
-20.0 81 40.93 2006 1474 22423 7985 81.8 1.546
-18.0 83 41.95 2067 1565 24090 8338 83.8 1.492
-16.0 85 42.97 2128 1659 25877 8683 85.7 1.441
-14.0 87 44.00 2190 1757 27792 9019 87.6 1.392
-12.0 89 45.02 2252 1858 29845 9343 89.3 1.345
-10.0 91 46.04 2314 1962 32049 9653 90.9 1.300
-08.0 93 47.07 2377 2069 34415 9949 92.4 1.256
-06.0 95 48.09 2439 2180 36959 10228 93.7 1.214
-04.0 97 49.11 2502 2293 39697 10489 95.0 1.174
-02.0 99 50.14 2565 2410 42646 10730 96.1 1.135
+00.0 101 51.16 2627 2529 45826 10950 97.0 1.098
+02.0 103 52.18 2690 2651 49262 11147 97.9 1.062
+04.0 105 53.21 2752 2775 52975 11320 98.6 1.028 ! Near Maximum !
+06.0 107 54.23 2814 2902 56998 11467 99.1 0.995 ! Near Maximum !
+08.0 109 55.25 2876 3031 61363 11588 99.6 0.962 !DANGEROUS LOAD-DO NOT USE!
+10.0 111 56.28 2938 3162 66105 11680 99.8 0.932 !DANGEROUS LOAD-DO NOT USE!
Results caused by ± 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba 101 51.16 2792 2857 56244 10801 100.0 1.004 ! Near Maximum !
Data for burning rate decreased by 10% relative to nominal value:
-Ba 101 51.16 2406 2121 36783 10248 87.9 1.220