Change of plans... Maybe?

GregoryB. · Aug 8, 2023

All this 280 talk is going to make me pull my #1 B out of the safe and finally work up a load and fire it. It has the 280/7mm Express markings on it.

nhenry · Aug 8, 2023

GregoryB. said:
All this 280 talk is going to make me pull my #1 B out of the safe and finally work up a load and fire it. It has the 280/7mm Express markings on it.

Do it

gerry · Aug 8, 2023

nhenry said:
Well, I went and dropped the stock off at the smith yesterday and after trying to find it for several minutes, he remembered that they cut and chambered the thing already!

My indecision was for nothing.

Awesome, now on to the 280 Rem project!

RL338 · Aug 8, 2023

nhenry said:
Well, I went and dropped the stock off at the smith yesterday and after trying to find it for several minutes, he remembered that they cut and chambered the thing already!

My indecision was for nothing.

He could stamp it 7mmExpress-280AI

Blkram · Aug 8, 2023

A few years back I had DrMike put some numbers into QuickLoad for pressures up to 65K in the 280 Rem, as I too was interested in seeing what could be achieved in the 280 Rem when loaded to the same pressures as the 270 Win, and was surprised at the surprisingly small increase in velocity gained by upping the pressure...perhaps he can run the numbers for a comparison on here to illustrate this?!?!
280 Rem w/ 24" barrel, with 150 gr AB or BT.

DrMike · Aug 9, 2023

Code:

Cartridge          : .280 Rem.
Bullet             : .284, 150, Nosler Accubond LR 58734 G7
Useable Case Capaci: 59.175 grain H2O = 3.842 cm³
Cartridge O.A.L. L6: 3.330 inch = 84.58 mm
Barrel Length      : 24.0 inch = 609.6 mm
Powder             : Alliant Reloder-17 *T

Predicted data by increasing and decreasing the given charge,
incremented in steps of 1.0% 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

-10.0   87    49.77   2777    2568   46028  10258    100.0    1.286
-09.0   88    50.32   2805    2621   47578  10318    100.0    1.267
-08.0   89    50.88   2834    2675   49180  10372    100.0    1.248
-07.0   90    51.43   2862    2728   50839  10424    100.0    1.229
-06.0   91    51.98   2890    2782   52555  10476    100.0    1.211
-05.0   92    52.54   2918    2836   54334  10527    100.0    1.193
-04.0   93    53.09   2946    2890   56174  10578    100.0    1.176  ! Near Maximum !
-03.0   94    53.64   2973    2945   58082  10627    100.0    1.158  ! Near Maximum !
-02.0   95    54.19   3001    2999   60056  10676    100.0    1.142  ! Near Maximum !
-01.0   96    54.75   3028    3054   62105  10724    100.0    1.125  ! Near Maximum !
+00.0   97    55.30   3056    3110   64228  10772    100.0    1.109  ! Near Maximum !
+01.0   98    55.85   3083    3165   66429  10818    100.0    1.093  !DANGEROUS LOAD-DO NOT USE!
+02.0   99    56.41   3110    3221   68712  10863    100.0    1.077  !DANGEROUS LOAD-DO NOT USE!
+03.0  100    56.96   3137    3277   71080  10908    100.0    1.062  !DANGEROUS LOAD-DO NOT USE!
+04.0  101    57.51   3163    3333   73534  10952    100.0    1.047  !DANGEROUS LOAD-DO NOT USE!
+05.0  101    58.07   3190    3390   76070  10995    100.0    1.032  !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 5% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 5% relative to nominal value:
+Ba     97    55.30   3110    3222   71147  10562    100.0    1.067  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 5% relative to nominal value:
-Ba     97    55.30   2987    2973   57685  11026    100.0    1.157  ! Near Maximum !

contra

Code:

Cartridge          : .280 Rem.
Bullet             : .284, 150, Nosler Accubond LR 58734 G7
Useable Case Capaci: 59.185 grain H2O = 3.843 cm³
Cartridge O.A.L. L6: 3.330 inch = 84.58 mm
Barrel Length      : 24.0 inch = 609.6 mm
Powder             : Alliant Reloder-17 *T

Predicted data by increasing and decreasing the given charge,
incremented in steps of 1.0% 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

-10.0   84    47.97   2682    2397   41327  10025     99.6    1.352
-09.0   85    48.50   2710    2447   42661  10101     99.8    1.332
-08.0   86    49.04   2738    2498   44040  10171     99.9    1.312
-07.0   87    49.57   2766    2548   45465  10236     99.9    1.293
-06.0   88    50.10   2794    2600   46937  10295    100.0    1.275
-05.0   88    50.64   2821    2651   48460  10349    100.0    1.256
-04.0   89    51.17   2849    2703   50034  10400    100.0    1.238  ! Near Maximum !
-03.0   90    51.70   2876    2754   51659  10450    100.0    1.221  ! Near Maximum !
-02.0   91    52.23   2903    2806   53340  10500    100.0    1.203  ! Near Maximum !
-01.0   92    52.77   2929    2858   55080  10549    100.0    1.186  ! Near Maximum !
+00.0   93    53.30   2956    2911   56873  10597    100.0    1.169  ! Near Maximum !
+01.0   94    53.83   2983    2963   58740  10645    100.0    1.153  !DANGEROUS LOAD-DO NOT USE!
+02.0   95    54.37   3009    3016   60664  10692    100.0    1.137  !DANGEROUS LOAD-DO NOT USE!
+03.0   96    54.90   3036    3069   62658  10738    100.0    1.121  !DANGEROUS LOAD-DO NOT USE!
+04.0   97    55.43   3062    3122   64723  10783    100.0    1.105  !DANGEROUS LOAD-DO NOT USE!
+05.0   98    55.97   3088    3176   66859  10828    100.0    1.090  !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 5% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 5% relative to nominal value:
+Ba     93    53.30   3015    3027   63024  10382    100.0    1.124  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 5% relative to nominal value:
-Ba     93    53.30   2883    2769   51173  10849     99.9    1.222  ! Near Maximum !