Quickload request for 257 Weatherby Mag

Elkibou

Beginner
May 26, 2024
3
1
I have looked high and low for load data and have struck out. On top of that, I have emailed Hammer bullets, Hornady and Nosler with zero results and none of them had load data for the powder I have on hand. The only data I have been able to locate is from Sierra, but it's a lead bullet load data and it also seems quite high for the starting and max load data. The following are my components:

92 grain Hammer Hunter bullet
Weatherby brass/84 grains H2O
GM215M primers
3.209" COAL
26" 1-10 barrel
Vihtavuori N560 and Reloder 26

Thanks in advance!
 
Code:
Cartridge          : .257 Weath. Mag
Bullet             : .257,  92, Hammer AH
Useable Case Capaci: 78.660 grain H2O = 5.107 cm³
Cartridge O.A.L. L6: 3.209 inch = 81.51 mm
Barrel Length      : 26.0 inch = 660.4 mm
Powder             : Alliant Reloder-26 *C

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   86    67.05   3359    2304   42803  13738     99.3    1.321
-09.0   87    67.80   3400    2361   44511  13837     99.6    1.298
-08.0   88    68.54   3441    2419   46281  13924     99.8    1.276
-07.0   89    69.29   3482    2477   48114  13999     99.9    1.253
-06.0   90    70.03   3523    2535   50014  14063    100.0    1.231
-05.0   91    70.78   3563    2593   51982  14115    100.0    1.210
-04.0   92    71.52   3603    2652   54022  14162    100.0    1.189
-03.0   93    72.27   3642    2710   56136  14209    100.0    1.169  ! Near Maximum !
-02.0   94    73.01   3682    2769   58328  14254    100.0    1.149  ! Near Maximum !
-01.0   95    73.76   3721    2827   60600  14299    100.0    1.129  ! Near Maximum !
+00.0   96    74.50   3759    2886   62956  14342    100.0    1.110  ! Near Maximum !
+01.0   97    75.25   3797    2945   65400  14385    100.0    1.092  !DANGEROUS LOAD-DO NOT USE!
+02.0   97    75.99   3835    3005   67935  14426    100.0    1.073  !DANGEROUS LOAD-DO NOT USE!
+03.0   98    76.74   3873    3064   70565  14466    100.0    1.055  !DANGEROUS LOAD-DO NOT USE!
+04.0   99    77.48   3911    3124   73294  14505    100.0    1.038  !DANGEROUS LOAD-DO NOT USE!
+05.0  100    78.23   3948    3184   76127  14543    100.0    1.021  !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     96    74.50   3849    3027   70634  14055    100.0    1.058  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 5% relative to nominal value:
-Ba     96    74.50   3646    2716   55354  14687    100.0    1.172  ! Near Maximum !

This data and the one following are for Absolute Hammer bullets. I have no data file for a 92 grain Hammer Hunter.
 
Last edited:
Welcome aboard. Let us know how these work out for you.

Code:
Cartridge          : .257 Weath. Mag
Bullet             : .257,  92, Hammer AH
Useable Case Capaci: 78.660 grain H2O = 5.107 cm³
Cartridge O.A.L. L6: 3.209 inch = 81.51 mm
Barrel Length      : 26.0 inch = 660.4 mm
Powder             : Vihtavuori N568 *C*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   96    72.72   3304    2230   41849  13905     91.8    1.329
-09.0   97    73.53   3350    2293   43583  14104     92.7    1.304
-08.0   98    74.34   3397    2357   45394  14296     93.4    1.280
-07.0   99    75.14   3443    2422   47288  14481     94.2    1.256
-06.0  100    75.95   3490    2488   49268  14657     94.8    1.233
-05.0  101    76.76   3537    2555   51339  14824     95.5    1.210
-04.0  103    77.57   3583    2623   53499  14983     96.1    1.187
-03.0  104    78.38   3630    2691   55746  15131     96.7    1.165  ! Near Maximum !
-02.0  105    79.18   3676    2761   58088  15271     97.2    1.144  ! Near Maximum !
-01.0  106    79.99   3723    2831   60530  15400     97.7    1.123  ! Near Maximum !
+00.0  107    80.80   3769    2902   63077  15518     98.1    1.102  ! Near Maximum !
+01.0  108    81.61   3815    2974   65734  15626     98.5    1.082  !DANGEROUS LOAD-DO NOT USE!
+02.0  109    82.42   3862    3046   68508  15723     98.9    1.062  !DANGEROUS LOAD-DO NOT USE!
+03.0  110    83.22   3908    3119   71404  15808     99.2    1.042  !DANGEROUS LOAD-DO NOT USE!
+04.0  111    84.03   3954    3193   74429  15881     99.4    1.023  !DANGEROUS LOAD-DO NOT USE!
+05.0  112    84.84   3999    3267   77591  15943     99.6    1.004  !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    107    80.80   3892    3094   70954  15460     99.7    1.048  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 5% relative to nominal value:
-Ba    107    80.80   3625    2685   55422  15294     95.0    1.165  ! Near Maximum !

That's stepping out there!
 
Welcome aboard. Let us know how these work out for you.

Code:
Cartridge          : .257 Weath. Mag
Bullet             : .257,  92, Hammer AH
Useable Case Capaci: 78.660 grain H2O = 5.107 cm³
Cartridge O.A.L. L6: 3.209 inch = 81.51 mm
Barrel Length      : 26.0 inch = 660.4 mm
Powder             : Vihtavuori N568 *C*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   96    72.72   3304    2230   41849  13905     91.8    1.329
-09.0   97    73.53   3350    2293   43583  14104     92.7    1.304
-08.0   98    74.34   3397    2357   45394  14296     93.4    1.280
-07.0   99    75.14   3443    2422   47288  14481     94.2    1.256
-06.0  100    75.95   3490    2488   49268  14657     94.8    1.233
-05.0  101    76.76   3537    2555   51339  14824     95.5    1.210
-04.0  103    77.57   3583    2623   53499  14983     96.1    1.187
-03.0  104    78.38   3630    2691   55746  15131     96.7    1.165  ! Near Maximum !
-02.0  105    79.18   3676    2761   58088  15271     97.2    1.144  ! Near Maximum !
-01.0  106    79.99   3723    2831   60530  15400     97.7    1.123  ! Near Maximum !
+00.0  107    80.80   3769    2902   63077  15518     98.1    1.102  ! Near Maximum !
+01.0  108    81.61   3815    2974   65734  15626     98.5    1.082  !DANGEROUS LOAD-DO NOT USE!
+02.0  109    82.42   3862    3046   68508  15723     98.9    1.062  !DANGEROUS LOAD-DO NOT USE!
+03.0  110    83.22   3908    3119   71404  15808     99.2    1.042  !DANGEROUS LOAD-DO NOT USE!
+04.0  111    84.03   3954    3193   74429  15881     99.4    1.023  !DANGEROUS LOAD-DO NOT USE!
+05.0  112    84.84   3999    3267   77591  15943     99.6    1.004  !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    107    80.80   3892    3094   70954  15460     99.7    1.048  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 5% relative to nominal value:
-Ba    107    80.80   3625    2685   55422  15294     95.0    1.165  ! Near Maximum !

That's stepping out there!
Thank you very much for the load data! The Reloder 26 was what I expected, however, the Vihtavuori N568 was not. I hate to aske again, but the original request was for Vihtavuori N560. Sorry for any confusion it may have caused. I really appreciate the quick response Doc!

Accuracy is FINAL! I'm just looking for starting load data to keep this safe!

Thanks again, I'm really appreciative!
 
Be careful, the design of the Absolute Hammer creates less pressure, you may hit pressure sooner with a Hammer Hunter. Start low and work up.
I'm using RL26 with 90g Absolute Hammers in my 25-06, it's amazing.
 
Thank you very much for the load data! The Reloder 26 was what I expected, however, the Vihtavuori N568 was not. I hate to aske again, but the original request was for Vihtavuori N560. Sorry for any confusion it may have caused. I really appreciate the quick response Doc!

Accuracy is FINAL! I'm just looking for starting load data to keep this safe!

Thanks again, I'm really appreciative!
Oops! Had my glasses off, apparently.

Code:
Cartridge          : .257 Weath. Mag
Bullet             : .257,  92, Hammer AH
Useable Case Capaci: 78.660 grain H2O = 5.107 cm³
Cartridge O.A.L. L6: 3.209 inch = 81.51 mm
Barrel Length      : 26.0 inch = 660.4 mm
Powder             : Vihtavuori N560 *C

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   89    65.70   3352    2296   44085  13595     94.2    1.284
-09.0   90    66.43   3393    2352   45697  13764     94.8    1.263
-08.0   91    67.16   3434    2408   47363  13927     95.3    1.242
-07.0   92    67.89   3474    2466   49084  14084     95.9    1.222
-06.0   93    68.62   3515    2524   50864  14234     96.4    1.203
-05.0   94    69.35   3555    2582   52703  14378     96.9    1.183
-04.0   95    70.08   3596    2641   54605  14515     97.3    1.164  ! Near Maximum !
-03.0   96    70.81   3636    2700   56572  14646     97.7    1.145  ! Near Maximum !
-02.0   97    71.54   3676    2760   58606  14769     98.1    1.127  ! Near Maximum !
-01.0   98    72.27   3716    2821   60709  14884     98.4    1.110  ! Near Maximum !
+00.0   99    73.00   3756    2882   62885  14992     98.7    1.092  ! Near Maximum !
+01.0  100    73.73   3796    2943   65136  15092     99.0    1.075  !DANGEROUS LOAD-DO NOT USE!
+02.0  101    74.46   3835    3004   67465  15184     99.3    1.058  !DANGEROUS LOAD-DO NOT USE!
+03.0  101    75.19   3874    3066   69875  15268     99.5    1.041  !DANGEROUS LOAD-DO NOT USE!
+04.0  102    75.92   3914    3129   72370  15344     99.6    1.025  !DANGEROUS LOAD-DO NOT USE!
+05.0  103    76.65   3953    3191   74954  15410     99.8    1.009  !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     99    73.00   3858    3041   69473  14896     99.9    1.045  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 5% relative to nominal value:
-Ba     99    73.00   3636    2700   56372  14862     96.3    1.146  ! Near Maximum !
 
Welcome aboard. Looking forward to seeing your results. I don’t own one but I’ve seen the 25 Bee kill everything from sage rats to bull elk. Amazing cartridge, good luck.
 
Welcome aboard. Looking forward to seeing your results. I don’t own one but I’ve seen the 25 Bee kill everything from sage rats to bull elk. Amazing cartridge, good luck.
It will be a couple weeks before I can get out to shoot, but I will post the results after range day.
 
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