Help Please.

[Kalahari]

I have been trying out some loads in my 7 x 64. They are Hornady 139gr. GMX down a 24" barrel. Powder is Viht N160. Now I got good groups with the following, 52.4gr., 53.2gr., 54.0gr., and 55.6gr.

So if some kind soul can run these through quickload it would be most helpful. Some idea of MV would help me decide which one has adequate downrange velocity for the monometal to behave in the required fashon.

Many thanks,

David.

PS. Although the top load had no pressure signs and the bolt lift was fine I got the impression it might be leaving me in a bit of a hurry! 😀

[Xtrema]

Here you go.

Cartridge          : 7 x 64 Brenneke
Bullet             : .284, 139, Hornady GMX 28270
Useable Case Capaci: 59.704 grain H2O = 3.877 cm³
Cartridge O.A.L. L6: 3.307 inch = 84.00 mm
Barrel Length      : 24.0 inch = 609.6 mm
Powder             : Vihtavuori N160 *C

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   79    41.92   2131    1402   23508   6826     78.6    1.669
-18.0   81    42.97   2184    1472   24934   7083     80.0    1.630
-16.0   83    44.02   2236    1544   26447   7339     81.4    1.592
-14.0   85    45.06   2289    1618   28056   7594     82.7    1.556
-12.0   87    46.11   2343    1694   29763   7847     84.0    1.519
-10.0   89    47.16   2397    1773   31577   8097     85.3    1.484
-08.0   91    48.21   2451    1854   33507   8343     86.5    1.450
-06.0   93    49.26   2505    1937   35557   8585     87.7    1.416
-04.0   95    50.30   2560    2022   37740   8822     88.9    1.384
-02.0   97    51.35   2615    2110   40065   9053     90.0    1.346
+00.0   99    52.40   2670    2200   42541   9278     91.0    1.309
+02.0  101    53.45   2725    2292   45183   9496     92.0    1.273
+04.0  103    54.50   2781    2386   48001   9706     93.0    1.238
+06.0  105    55.54   2836    2483   51012   9907     93.9    1.204
+08.0  107    56.59   2892    2581   54231  10099     94.8    1.171  ! Near Maximum !
+10.0  109    57.64   2948    2682   57658  10280     95.5    1.139  ! Near Maximum !

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     99    52.40   2824    2462   50602   9634     96.8    1.211
Data for burning rate decreased by 10% relative to nominal value:
-Ba     99    52.40   2484    1904   35140   8553     82.3    1.421

[Kalahari]

Many thanks. Very useful and very kind of you.

 

David.