257 Bob
Cartridge : .257 Roberts
Bullet : .257, 100, Nosler BalTip 25100
Useable Case Capaci: 48.671 grain H2O = 3.160 cm³
Cartridge O.A.L. L6: 2.775 inch = 70.49 mm
Barrel Length : 22.0 inch = 558.8 mm
Powder : Ramshot Big Game
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 67 32.00 2289 1164 24144 7957 87.0 1.501
-18.0 69 32.80 2344 1220 25589 8231 88.3 1.467
-16.0 70 33.60 2399 1278 27118 8500 89.6 1.433
-14.0 72 34.40 2453 1337 28735 8764 90.8 1.402
-12.0 74 35.20 2508 1397 30448 9021 91.9 1.371
-10.0 75 36.00 2563 1459 32261 9271 93.0 1.341
-08.0 77 36.80 2618 1522 34178 9513 94.0 1.311
-06.0 79 37.60 2673 1587 36210 9746 94.9 1.282
-04.0 80 38.40 2728 1652 38360 9968 95.8 1.250
-02.0 82 39.20 2782 1719 40640 10180 96.5 1.217
+00.0 84 40.00 2837 1787 43053 10381 97.2 1.184
+02.0 85 40.80 2891 1856 45608 10569 97.9 1.153 ! Near Maximum !
+04.0 87 41.60 2945 1926 48288 10745 98.4 1.124 ! Near Maximum !
+06.0 89 42.40 2999 1997 51111 10907 98.9 1.095 !DANGEROUS LOAD-DO NOT USE!
+08.0 90 43.20 3053 2069 54096 11054 99.3 1.067 !DANGEROUS LOAD-DO NOT USE!
+10.0 92 44.00 3106 2142 57254 11187 99.6 1.040 !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 84 40.00 2981 1973 51477 10324 99.9 1.095 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 84 40.00 2649 1558 35128 9890 90.3 1.295
257 Bob +P
Cartridge : .257 Roberts +P+
Bullet : .257, 100, Nosler BalTip 25100
Useable Case Capaci: 48.669 grain H2O = 3.160 cm³
Cartridge O.A.L. L6: 2.775 inch = 70.49 mm
Barrel Length : 22.0 inch = 558.8 mm
Powder : Ramshot Big Game
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 72 34.40 2454 1337 28738 8764 90.8 1.402
-18.0 74 35.26 2513 1402 30582 9040 92.0 1.369
-16.0 76 36.12 2572 1468 32542 9308 93.1 1.336
-14.0 77 36.98 2631 1537 34627 9566 94.2 1.304
-12.0 79 37.84 2690 1606 36844 9813 95.2 1.273
-10.0 81 38.70 2748 1677 39203 10049 96.1 1.238
-08.0 83 39.56 2807 1750 41711 10272 96.9 1.202
-06.0 85 40.42 2866 1823 44382 10481 97.6 1.168
-04.0 86 41.28 2924 1898 47204 10676 98.2 1.135
-02.0 88 42.14 2982 1974 50180 10856 98.7 1.104 ! Near Maximum !
+00.0 90 43.00 3039 2051 53338 11019 99.2 1.074 ! Near Maximum !
+02.0 92 43.86 3096 2129 56692 11165 99.5 1.044 ! Near Maximum !
+04.0 94 44.72 3153 2208 60256 11293 99.8 1.016 !DANGEROUS LOAD-DO NOT USE!
+06.0 95 45.58 3210 2287 64045 11404 99.9 0.989 !DANGEROUS LOAD-DO NOT USE!
+08.0 97 46.44 3265 2368 68075 11495 100.0 0.963 !DANGEROUS LOAD-DO NOT USE!
+10.0 99 47.30 3321 2449 72366 11572 100.0 0.937 !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 90 43.00 3171 2233 63619 10689 100.0 0.996 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 90 43.00 2855 1810 43352 10793 94.1 1.175
