270wsm N560 150grain barnes txs load help.

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Punchie

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Hi,

Im looking to work a load for my tikka 270wsm.
I have 150 grain barnes txs, Winchester brass, cci large magnum primers and vihtavuori N560.


Vihtavuori site has N560 data for 270 wsm but only for 140 grain and 160 grain projectiles.
Branes dosent list N560 as a powder.
Im looking for a safe min and max to start the development.

Any help would be much appreciated.
 
Punchie said:
Hi,

Im looking to work a load for my tikka 270wsm.
I have 150 grain barnes txs, Winchester brass, cci large magnum primers and vihtavuori N560.


Vihtavuori site has N560 data for 270 wsm but only for 140 grain and 160 grain projectiles.
Barnes doesn't list N560 as a powder.
Im looking for a safe min and max to start the development.

Any help would be much appreciated.
Click to expand...

I am sorry, I do not have any info as far as the 270 WSM is concerned.
However, I would like to make a comment regarding N560. I have and use
it....it is good for a number of applications.

That being said, I find it to be just a bit faster burning than most burn
rate charts would indicate.

One chart shows it right next to Norma MRP. It is definitely quicker than MRP
In my 6.5 x 55 Swede with the 140 grain AB, it takes 3 grains less of N560
to reach the same velocity as MRP.

Just relating personal experience with N560. Dave.
 
Vihtavuori's data on their site looks fairly mild. A 270WSM will not max out at 3000 fps with a 140gr like they suggest

hopefully this Quickload data can help guide you

Code: 
Cartridge          : .[B]270 WSM[/B]
Bullet             : .277, [B]150, Barnes 'TSX'[/B] 30269
Useable Case Capaci: 71.417 grain H2O = 4.637 cm³
Cartridge O.A.L. L6: 2.860 inch = 72.64 mm
Barrel Length      : 24.0 inch = 609.6 mm
Powder             : [B]Vihtavuori N560[/B]

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    56.70   2796    2603   48879  12373     96.1    1.263
-09.0   85    57.33   2824    2656   50166  12514     96.4    1.250
-08.0   86    57.96   2853    2710   51485  12651     96.8    1.237
-07.0   87    58.59   2881    2765   52840  12786     97.1    1.224
-06.0   88    59.22   2910    2820   54230  12917     97.4    1.212
-05.0   89    59.85   2938    2875   55657  13045     97.7    1.200  ! Near Maximum !
-04.0   90    60.48   2967    2931   57122  13169     98.0    1.188  ! Near Maximum !
-03.0   91    61.11   2995    2988   58626  13289     98.2    1.176  ! Near Maximum !
-02.0   92    61.74   3024    3045   60171  13406     98.5    1.164  ! Near Maximum !
-01.0   93    62.37   3052    3103   61757  13519     98.7    1.152  ! Near Maximum !
[B]+00.0   94    63.00   3081    3161   63388  13627     98.9    1.141  ! Near Maximum ![/B]
+01.0   95    63.63   3109    3220   65068  13732     99.1    1.129  !DANGEROUS LOAD-DO NOT USE!
+02.0   96    64.26   3137    3279   66802  13831     99.3    1.118  !DANGEROUS LOAD-DO NOT USE!
+03.0   96    64.89   3166    3338   68591  13927     99.4    1.106  !DANGEROUS LOAD-DO NOT USE!
+04.0   97    65.52   3194    3399   70438  14018     99.6    1.095  !DANGEROUS LOAD-DO NOT USE!
+05.0   98    66.15   3223    3459   72345  14103     99.7    1.084  !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     94    63.00   3216    3445   73909  13282    100.0    1.080  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba     94    63.00   2900    2800   52656  13283     93.7    1.213
 
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