The UK's Finest Independent Forum for Shooters and Gun Owners. Est 2010.

Could someone run a load for me for a theoretical muzzle velocity and energy, please?

6.8 Remington SPC

115gn Sierra Match King (BC 0.324)
23gns of IMR 4198
COL 2.260"

Ta.

Cartridge : 6.8 mm Rem SPC
Bullet : .277, 115, Sierra HPBT MatchK 1815
Useable Case Capaci: 27.721 grain H2O = 1.800 cm³
Cartridge O.A.L. L6: 2.260 inch = 57.40 mm
Barrel Length : 30.0 inch = 762.0 mm
Powder : IMR 4198

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 80 18.40 2201 1237 27986 2970 97.0 1.714
-18.0 82 18.86 2246 1288 29630 3037 97.6 1.676
-16.0 84 19.32 2291 1340 31362 3100 98.1 1.638
-14.0 86 19.78 2335 1392 33189 3160 98.6 1.602
-12.0 88 20.24 2378 1444 35118 3216 99.0 1.567
-10.0 90 20.70 2421 1497 37150 3267 99.4 1.534
-08.0 92 21.16 2464 1551 39295 3314 99.6 1.498
-06.0 94 21.62 2506 1604 41560 3357 99.8 1.464
-04.0 96 22.08 2548 1658 43951 3395 99.9 1.431
-02.0 98 22.54 2590 1712 46476 3429 100.0 1.399
+00.0 100 23.00 2630 1767 49145 3458 100.0 1.368
+02.0 102 23.46 2671 1821 51969 3487 100.0 1.338 ! Near Maximum !
+04.0 104 23.92 2710 1876 54955 3515 100.0 1.310 ! Near Maximum !
+06.0 106 24.38 2750 1931 58118 3542 100.0 1.282 !DANGEROUS LOAD-DO NOT USE!
+08.0 108 24.84 2789 1986 61467 3569 100.0 1.256 !DANGEROUS LOAD-DO NOT USE!
+10.0 110 25.30 2828 2042 65018 3595 100.0 1.230 !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 100 23.00 2703 1865 57670 3299 100.0 1.297 ! Near Maximum !
Data for burning rate decreased by 10% relative to nominal value:
-Ba 100 23.00 2519 1620 41213 3578 98.1 1.465

Thanks Adam, I appreciate it!

Er, you couldn't run it again for me could you please? But add a 20" barrel that I omitted earlier...... Doh!

Ta.

Cartridge : 6.8 mm Rem SPC
Bullet : .277, 115, Sierra HPBT MatchK 1815
Useable Case Capaci: 27.721 grain H2O = 1.800 cm³
Cartridge O.A.L. L6: 2.260 inch = 57.40 mm
Barrel Length : 20.0 inch = 508.0 mm
Powder : IMR 4198

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 80 18.40 2032 1055 27986 4695 94.2 1.322
-18.0 82 18.86 2076 1101 29630 4823 95.0 1.291
-16.0 84 19.32 2120 1148 31362 4946 95.8 1.262
-14.0 86 19.78 2164 1195 33189 5064 96.5 1.233
-12.0 88 20.24 2207 1244 35118 5177 97.2 1.205
-10.0 90 20.70 2250 1293 37150 5285 97.8 1.178
-08.0 92 21.16 2293 1342 39295 5386 98.3 1.149
-06.0 94 21.62 2335 1393 41560 5481 98.7 1.121
-04.0 96 22.08 2378 1443 43951 5570 99.1 1.093
-02.0 98 22.54 2419 1495 46476 5652 99.4 1.067
+00.0 100 23.00 2461 1547 49145 5727 99.7 1.042
+02.0 102 23.46 2502 1599 51969 5794 99.8 1.017 ! Near Maximum !
+04.0 104 23.92 2543 1652 54955 5854 100.0 0.994 ! Near Maximum !
+06.0 106 24.38 2584 1705 58118 5907 100.0 0.971 !DANGEROUS LOAD-DO NOT USE!
+08.0 108 24.84 2624 1758 61467 5954 100.0 0.949 !DANGEROUS LOAD-DO NOT USE!
+10.0 110 25.30 2664 1812 65018 5999 100.0 0.927 !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 100 23.00 2546 1655 57670 5495 100.0 0.980 ! Near Maximum !
Data for burning rate decreased by 10% relative to nominal value:
-Ba 100 23.00 2339 1397 41213 5733 95.9 1.122

Thanks again, Adam.