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H-870 load data (Read 1381 times)
billsmith
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H-870 load data
Aug 20th, 2019 at 9:27pm
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i have a lot of WC-872 powder.  this is very close to H-870 and AA-8700.  i would like to use it, if i can, to load some 220 gr loads.  i can find no data for this powder at all.  likewise i can find only very scant data for H-870 for any cartridges. have any of you tried WC-872 or H-870 or AA-8700 in this rifle?  any suggestions on starting load??

thanks.
  
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Parashooter
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Re: H-870 load data
Reply #1 - Aug 20th, 2019 at 10:20pm
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You may have difficulty stuffing enough WC872 into the case to achieve even normal velocity. Expect lots of unburned (and wasted) granules since this 20mm cannon powder burns pretty slow (in most lots, though some may be quicker).

Here are some QuickLOAD estimates (not real data!) for H870 in .30-40 -

Cartridge          : .30-40 Krag
Bullet             : .308, 220, Sierra SPRN 2180
Cartridge O.A.L. L6: 3.089 inch or 78.46 mm
Barrel Length      : 30.0 inch or 762.0 mm
Powder             : Hodgdon H870

Predicted data by increasing and decreasing the given charge,
incremented in steps of 2.941% 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

-11.8   88    40.54   1616    1276   16135   3951     63.7    2.534
-08.8   91    41.90   1675    1370   17466   4224     66.2    2.508
-05.9   94    43.25   1736    1473   18932   4504     68.6    2.418
-02.9   97    44.60   1800    1583   20551   4787     71.1    2.330
+00.0  100    45.95   1866    1701   22341   5072     73.5    2.243
+02.9  103    47.30   1934    1827   24329   5358     76.0    2.158
+05.9  106    48.65   2004    1962   26538   5641     78.4    2.075


Note the absurd "Burnt %" figures.
  
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madsenshooter
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Re: H-870 load data
Reply #2 - Aug 22nd, 2019 at 5:49pm
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