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powder charge & pressure
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<toto>
posted
I would appreciate someone running a receipt for me on one of those computer programs that tells what a particular charge vs pressure. I have wc872 &wc860 which i'm told to use h870 data. I am loading for STW. I would like to know with 94,95 96gr. 150nos.bt. thanks fws
 
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<Scott H>
posted
code:
Cartridge           : 7 mm STW
Bullet              : .284, 150, NOS BalTip 28150
Cartridge O.A.L. L6 : 3.650 inch or 92.71 mm
Barrel Length       : 26.0 inch or 660.4 mm
Powder              : Hodgdon H870
Predicted data by increasing and decreasing the given charge,
incremented in steps of 1.064% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !
Step    Fill. Charge   Vel.  Energy   Pmax   Pmuz  Prop.Burnt Btime
 %       %    Grains   fps   ft.lbs    psi    psi      %        ms
+05.3  109    94.79   3461    3990   67577  16383     99.7    1.166  !DANGEROUS LOAD-DO NOT USE!
+04.3  108    93.83   3420    3896   64893  16294     99.5    1.188  !DANGEROUS LOAD-DO NOT USE!
+03.2  107    92.87   3379    3803   62324  16192     99.2    1.211  ! HOT LOAD !
+02.1  106    91.91   3338    3710   59865  16078     98.9    1.233  ! HOT LOAD !
+01.1  105    90.96   3296    3619   57509  15953     98.6    1.257  ! HOT LOAD !
+00.0  104    90.00   3255    3528   55251  15817     98.2    1.280  ! HOT LOAD !
-01.1  103    89.04   3213    3439   53080  15670     97.8    1.305
-02.1  102    88.09   3172    3351   50991  15514     97.3    1.329
-03.2  101    87.13   3131    3265   48994  15348     96.8    1.354
-04.3   99    86.17   3090    3179   47085  15172     96.2    1.380
-05.3   98    85.21   3048    3095   45261  14988     95.7    1.406
-06.4   97    84.26   3007    3012   43517  14795     95.0    1.433
-07.4   96    83.30   2966    2930   41847  14594     94.4    1.460
-08.5   95    82.34   2925    2850   40249  14386     93.7    1.487
-09.6   94    81.38   2885    2771   38719  14170     92.9    1.516
-10.6   93    80.43   2844    2694   37256  13949     92.2    1.544
 
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Stonecreek
one of us
posted Hide Post
Toto: The advice to use H870 data as a starting point for WC 860 and WC 872 is safe advice, and conservative.

Both WC powders are fairly similar in burning rate (at least in the lots I have) and are quite a bit slower than H870.

Watch your chronograph readings and pressure signs, and you can increase rather substantially over H870. I have had a bit better luck with WC 872, which actually seems a bit faster than WC 860, but each lot of surplus powder is a rule unto itself.

I think you will find it hard to overload the 7STW with 150 grain bullets and either of these powders without a great deal of compression.

 
Posts: 13238 | Location: Henly, TX, USA | Registered: 04 April 2001Reply With Quote
<toto>
posted
Scott and Stonecreek, I want to thank you for you for the info. I loaded 92 gr. of both powders yesterday. I had no pressure , but no velocity. The day before I got 3530 with 84 gr. of r25, 3475 with 81gr 7828 and 3250 with 83gr of h1000. I was hoping to get 3400 with the slower powder with reduced pressure. Anyway I do appreciate your help. Will let you know how it turns out. thanks fws
 
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