Load data 6.5 creedmore with vihtavuori n555 and 140 nosler cc

robgreen · Sep 4, 2024

Good day all, I'm new here and looking for advice.

Looking for any advice on personal load data for Mt 6.5 creed with the following components, rifle is a sauer s100 field shoot with 1 in 8 twist 24 inch barrel
Vihtavuori N555 powder
Nosler 140 custom competition
Lapua srp
Cci 450 primers

Vihtavuori website doesn't list the 140 custom competition bullets, but the nosler ballistic tip is.
Is the ballistic tip comparable to the cc? As I'm using their 42grain n555 max charge on the custom competition bullet and not reaching 2700fps ?

Anyone have and experience with the same components I have?
Asking for advice?

Thank you

TackDriver284 · Sep 4, 2024

I have used similar bullet weights in my Creedmoor, and have not reached max velocity as stated in the manuals at times, it depends on case capacity and chamber dimensions. Would you know the H20 water capacity on your fired cases? Perhaps you can give us the H20 case capacity, exact velocity given for that powder charge, ambient temp, and OAL length of your cartridge and I can tweak the burn rate values to get a more accurate assessment.

Code:

Cartridge          : 6.5 Creedmoor Hornady
Bullet             : .264, 140, Nosler CC HPBT 26725
Useable Case Capaci: 45.762 grain H2O = 2.971 cm³
Cartridge O.A.L. L6: 2.800 inch = 71.12 mm
Barrel Length      : 24.0 inch = 609.6 mm
Powder             : Vihtavuori N555 *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   98    40.50   2577    2065   43188   9382     99.3    1.410
-09.0   99    40.95   2606    2110   44729   9450     99.5    1.388
-08.0  100    41.40   2634    2157   46327   9513     99.7    1.365
-07.0  101    41.85   2662    2203   47982   9571     99.8    1.344
-06.0  102    42.30   2690    2249   49697   9624     99.9    1.323
-05.0  103    42.75   2718    2296   51475   9671    100.0    1.302
-04.0  104    43.20   2746    2344   53318   9713    100.0    1.281
-03.0  106    43.65   2773    2391   55230   9749    100.0    1.262  ! Near Maximum !
-02.0  107    44.10   2801    2439   57212   9785    100.0    1.242  ! Near Maximum !
-01.0  108    44.55   2828    2486   59268   9819    100.0    1.223  ! Near Maximum !
+00.0  109    45.00   2855    2534   61402   9853    100.0    1.204  ! Near Maximum !
+01.0  110    45.45   2882    2583   63617   9886    100.0    1.185  !DANGEROUS LOAD-DO NOT USE!
+02.0  111    45.90   2909    2631   65917   9918    100.0    1.167  !DANGEROUS LOAD-DO NOT USE!
+03.0  112    46.35   2936    2680   68305   9949    100.0    1.149  !DANGEROUS LOAD-DO NOT USE!
+04.0  113    46.80   2963    2729   70786   9979    100.0    1.132  !DANGEROUS LOAD-DO NOT USE!
+05.0  114    47.25   2990    2779   73365  10008    100.0    1.115  !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    109    45.00   2964    2731   75803   9405    100.0    1.110  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba    109    45.00   2687    2244   47511  10224     98.1    1.334

robgreen · Sep 4, 2024

Hi thanks so much, I'm not sure of the h2o volume of the spent case.
My base to ogive is 2.650" and that is a 20 thousandths jump to the lands. The velocity I got at 42grains was 2635fps.
I did go to 43grains but didn't get the velocity. I will re do the speeds this weekend and record the velocities