243 20 in. barrel velocities?

jr1968 · May 3, 2014

I have a savage axis with a 20 in. barrel , with 9:25 twist. I don't have a chron, and was wondering
what the difference in velocity compared to a 22 in barrel ?

jr1968

DrMike · May 3, 2014

About 79 fps.

Cartridge : .243 Win.
Bullet : .243, 100, Nosler PART SP 35642
Useable Case Capaci: 49.323 grain H2O = 3.203 cm³
Cartridge O.A.L. L6: 2.710 inch = 68.83 mm
Barrel Length : 20.0 inch = 508.0 mm
Powder : Alliant Reloder-22

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 82 37.60 2312 1187 29736 11072 85.4 1.432
-18.0 84 38.54 2374 1251 31828 11485 87.1 1.396
-16.0 86 39.48 2437 1318 34073 11889 88.6 1.361
-14.0 88 40.42 2500 1388 36485 12282 90.1 1.327
-12.0 90 41.36 2563 1459 39073 12661 91.5 1.284
-10.0 92 42.30 2627 1533 41860 13025 92.8 1.242
-08.0 94 43.24 2691 1608 44859 13372 94.0 1.203
-06.0 96 44.18 2756 1686 48087 13700 95.2 1.164
-04.0 98 45.12 2820 1766 51567 14006 96.2 1.127 ! Near Maximum !
-02.0 100 46.06 2884 1847 55289 14290 97.1 1.091 ! Near Maximum !
+00.0 102 47.00 2948 1930 59269 14549 97.8 1.057 ! Near Maximum !
+02.0 104 47.94 3013 2015 63548 14781 98.5 1.023 !DANGEROUS LOAD-DO NOT USE!
+04.0 106 48.88 3077 2102 68153 14985 99.1 0.991 !DANGEROUS LOAD-DO NOT USE!
+06.0 108 49.82 3140 2190 73112 15158 99.5 0.960 !DANGEROUS LOAD-DO NOT USE!
+08.0 110 50.76 3204 2279 78461 15300 99.8 0.930 !DANGEROUS LOAD-DO NOT USE!
+10.0 112 51.70 3267 2370 84237 15408 100.0 0.901 !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 102 47.00 3106 2142 72001 14354 100.0 0.971 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 102 47.00 2738 1664 47242 13880 90.8 1.169

Cartridge : .243 Win.
Bullet : .243, 100, Nosler PART SP 35642
Useable Case Capaci: 49.323 grain H2O = 3.203 cm³
Cartridge O.A.L. L6: 2.710 inch = 68.83 mm
Barrel Length : 22.0 inch = 558.8 mm
Powder : Alliant Reloder-22

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 82 37.60 2387 1265 29736 10150 87.1 1.503
-18.0 84 38.54 2450 1333 31828 10509 88.7 1.465
-16.0 86 39.48 2514 1403 34073 10858 90.2 1.428
-14.0 88 40.42 2577 1475 36485 11195 91.6 1.392
-12.0 90 41.36 2641 1549 39073 11519 92.9 1.348
-10.0 92 42.30 2706 1625 41860 11827 94.1 1.305
-08.0 94 43.24 2770 1704 44859 12117 95.2 1.264
-06.0 96 44.18 2834 1784 48087 12389 96.2 1.224
-04.0 98 45.12 2898 1865 51567 12641 97.1 1.185 ! Near Maximum !
-02.0 100 46.06 2963 1949 55289 12870 97.9 1.148 ! Near Maximum !
+00.0 102 47.00 3027 2034 59269 13076 98.5 1.112 ! Near Maximum !
+02.0 104 47.94 3090 2121 63548 13256 99.1 1.078 !DANGEROUS LOAD-DO NOT USE!
+04.0 106 48.88 3154 2209 68153 13411 99.5 1.045 !DANGEROUS LOAD-DO NOT USE!
+06.0 108 49.82 3217 2298 73112 13537 99.8 1.013 !DANGEROUS LOAD-DO NOT USE!
+08.0 110 50.76 3280 2388 78461 13634 100.0 0.982 !DANGEROUS LOAD-DO NOT USE!
+10.0 112 51.70 3342 2480 84237 13701 100.0 0.952 !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 102 47.00 3179 2245 72001 12773 100.0 1.024 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 102 47.00 2818 1763 47242 12611 92.1 1.229