Have a look at the following table for 20 inch barrel Speer BTSP and N160, hope it helps.
Cartridge : .243 Win.
Bullet : .243, 100, Speer BTSP 1220
Useable Case Capaci: 49.784 grain H2O = 3.232 cm³
Cartridge O.A.L. L6: 2.710 inch = 68.83 mm
Barrel Length : 20.0 inch = 508.0 mm
Powder : Vihtavuori N160
Predicted data by increasing and decreasing the given charge,
incremented in steps of 0.227% 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
-02.3 98 43.00 2672 1585 48683 12187 93.8 1.156
-02.0 98 43.10 2678 1593 49026 12219 93.9 1.153
-01.8 98 43.20 2684 1600 49372 12249 94.0 1.149
-01.6 98 43.30 2691 1608 49720 12280 94.1 1.145
-01.4 99 43.40 2697 1615 50070 12311 94.2 1.141
-01.1 99 43.50 2704 1623 50423 12341 94.3 1.138
-00.9 99 43.60 2710 1631 50779 12371 94.4 1.134
-00.7 99 43.70 2716 1638 51137 12402 94.6 1.130
-00.5 100 43.80 2723 1646 51498 12432 94.7 1.126 ! Near Maximum !
-00.2 100 43.90 2729 1654 51861 12461 94.8 1.122 ! Near Maximum !
+00.0 100 44.00 2735 1662 52227 12491 94.9 1.119 ! Near Maximum !
+00.2 100 44.10 2742 1669 52595 12520 95.0 1.115 ! Near Maximum !
+00.5 100 44.20 2748 1677 52967 12550 95.1 1.112 ! Near Maximum !
+00.7 101 44.30 2755 1685 53340 12579 95.2 1.108 ! Near Maximum !
+00.9 101 44.40 2761 1693 53717 12607 95.3 1.104 ! Near Maximum !
+01.1 101 44.50 2767 1701 54096 12636 95.4 1.101 ! Near Maximum !
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 44.00 2878 1840 61548 12711 99.0 1.037 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 100 44.00 2557 1452 43094 11735 87.3 1.223