QL for .257 Roberts & .270 Winchester

[SenderoAg]

Thanks for your help in advance. I have two loads, I’ve been shooting for many years with older data that has never caused any issues in either rifle. I’d just like to see what muzzle fps they are generating.

Can someone please run a Quick Load on both of these 2 loads ?

270 Winchester – 150 grain Nosler Partition, Federal Large rifle primers, 57.5 grains of H4831 - 24" barrel

257 Roberts – 100 Barnes Tipped Triple Shock, Federal Large rifle primers, 44.4 grains of IMR 4350 - 22" barrel

They both are a little warm, per newer manuals – but I used older manuals many years ago to work them up and have NO issues at all. Both just very accurate.

Thanks very much in advance for your kind assistance.

 

[DrMike]

Cartridge          : .270 Win. (SAAMI)
Bullet             : .277, 150, Nosler PART SP 16323
Useable Case Capaci: 60.130 grain H2O = 3.904 cm³
Cartridge O.A.L. L6: 3.340 inch = 84.84 mm
Barrel Length      : 24.0 inch = 609.6 mm
Powder             : Hodgdon H4831

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    51.75   2624    2294   43925  10472     93.2    1.347
-09.0   97    52.33   2655    2348   45438  10606     93.7    1.326
-08.0   98    52.90   2686    2402   47006  10736     94.2    1.305
-07.0   99    53.48   2716    2458   48635  10863     94.7    1.285
-06.0  100    54.05   2747    2514   50324  10987     95.2    1.265
-05.0  101    54.63   2778    2570   52076  11107     95.6    1.245
-04.0  102    55.20   2809    2627   53896  11223     96.1    1.225
-03.0  104    55.78   2839    2685   55785  11335     96.5    1.206  ! Near Maximum !
-02.0  105    56.35   2870    2744   57749  11444     96.9    1.188  ! Near Maximum !
-01.0  106    56.93   2901    2803   59790  11548     97.2    1.169  ! Near Maximum !
+00.0  107    57.50   2932    2863   61909  11647     97.6    1.151  ! Near Maximum !
+01.0  108    58.08   2963    2924   64116  11743     97.9    1.133  ! Near Maximum !
+02.0  109    58.65   2994    2986   66403  11833     98.2    1.116  !DANGEROUS LOAD-DO NOT USE!
+03.0  110    59.23   3025    3048   68774  11919     98.5    1.098  !DANGEROUS LOAD-DO NOT USE!
+04.0  111    59.80   3056    3110   71236  11999     98.7    1.081  !DANGEROUS LOAD-DO NOT USE!
+05.0  112    60.38   3087    3174   73799  12075     99.0    1.065  !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    107    57.50   3072    3143   74033  11516    100.0    1.068  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba    107    57.50   2747    2513   50510  11194     91.1    1.258

You have room to increase your load somewhat, though I don't see any reason to do so.

 

[DrMike]

Similar situation with the aforementioned load.

Cartridge          : .257 Roberts +P+ (not SAAMI)
Bullet             : .257, 100, Barnes 'TSX'BT 30222
Useable Case Capaci: 48.644 grain H2O = 3.158 cm³
Cartridge O.A.L. L6: 2.775 inch = 70.49 mm
Barrel Length      : 22.0 inch = 558.8 mm
Powder             : IMR 4350

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   90    39.96   2716    1638   41094   9697     90.8    1.198
-09.0   91    40.40   2745    1674   42332   9826     91.3    1.184
-08.0   92    40.85   2775    1710   43636   9953     91.8    1.170
-07.0   93    41.29   2804    1746   44971  10078     92.3    1.157
-06.0   94    41.74   2834    1783   46346  10202     92.8    1.144
-05.0   95    42.18   2864    1821   47758  10322     93.3    1.131
-04.0   96    42.62   2893    1859   49210  10441     93.8    1.118
-03.0   97    43.07   2923    1897   50703  10557     94.2    1.105  ! Near Maximum !
-02.0   98    43.51   2953    1936   52238  10670     94.7    1.092  ! Near Maximum !
-01.0   99    43.96   2982    1975   53822  10781     95.1    1.075  ! Near Maximum !
+00.0  100    44.40   3012    2015   55457  10889     95.5    1.060  ! Near Maximum !
+01.0  101    44.84   3042    2055   57147  10994     95.9    1.046  ! Near Maximum !
+02.0  102    45.29   3072    2095   58892  11096     96.3    1.032  !DANGEROUS LOAD-DO NOT USE!
+03.0  103    45.73   3101    2136   60695  11195     96.6    1.018  !DANGEROUS LOAD-DO NOT USE!
+04.0  104    46.18   3131    2177   62558  11291     97.0    1.004  !DANGEROUS LOAD-DO NOT USE!
+05.0  105    46.62   3161    2219   64484  11383     97.3    0.990  !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    100    44.40   3160    2218   65042  11002     99.3    0.987  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba    100    44.40   2825    1773   46035  10312     88.4    1.148

 

[SenderoAg]

Thanks very much!

Just about what I thought!

 

[SJB358]

Those are a couple of classic loads for those two cartridges!