IMR 7977

obrinca

Beginner
Jan 14, 2016
2
0
IS there a suggested load range for IMR 7977 in a 7mm Remington Mag using the 168 gr ABLR bullet?

Thanks

Craig O.
 
Welcome aboard, obrinca. Always glad to see new people posting. Here is a QL projection that may help.

Code:
Cartridge          : 7 mm Rem. Mag.(SAAMI)
Bullet             : .284, 168, Nosler Accubond LR 58623 G7
Useable Case Capaci: 71.513 grain H2O = 4.643 cm³
Cartridge O.A.L. L6: 3.290 inch = 83.57 mm
Barrel Length      : 24.0 inch = 609.6 mm
Powder             : IMR 7977 Enduron

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   92    59.85   2515    2359   43466  10371     87.8    1.425
-09.0   93    60.52   2544    2415   44890  10520     88.4    1.403
-08.0   94    61.18   2573    2470   46363  10667     89.0    1.382
-07.0   95    61.85   2603    2527   47887  10812     89.6    1.360
-06.0   96    62.51   2632    2585   49464  10955     90.1    1.340
-05.0   97    63.18   2662    2643   51096  11096     90.7    1.319
-04.0   98    63.84   2691    2702   52787  11235     91.2    1.299  ! Near Maximum !
-03.0   99    64.51   2721    2762   54538  11371     91.7    1.280  ! Near Maximum !
-02.0  100    65.17   2751    2823   56352  11505     92.3    1.260  ! Near Maximum !
-01.0  101    65.84   2781    2884   58232  11636     92.8    1.241  ! Near Maximum !
+00.0  102    66.50   2810    2946   60180  11765     93.2    1.222  ! Near Maximum !
+01.0  103    67.17   2840    3010   62201  11890     93.7    1.204  !DANGEROUS LOAD-DO NOT USE!
+02.0  104    67.83   2871    3074   64297  12013     94.2    1.186  !DANGEROUS LOAD-DO NOT USE!
+03.0  105    68.50   2901    3139   66472  12132     94.6    1.168  !DANGEROUS LOAD-DO NOT USE!
+04.0  106    69.16   2931    3204   68730  12248     95.0    1.151  !DANGEROUS LOAD-DO NOT USE!
+05.0  107    69.83   2961    3271   71075  12360     95.4    1.133  !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    102    66.50   2952    3251   70231  12065     98.0    1.139  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba    102    66.50   2637    2593   50434  11037     85.7    1.328

Start low and work up, watching for pressure signs.
 
Thanks for the information. I've worked my way up to 67.50 grains with no signs of over pressure. I'm getting an average velocity of 2770.8 fps out of a 26" bbl.

I think I'll stick with my 66.40 grain IMR 7828SSC load and plug the temperature variances to the Applied Ballistics app. That load is giving my a little over 2900 fps and sub MOA groups. I guess that falls under the "if it ain't broke don't fix it" category.

Thanks again.
 
You're obviously getting fine velocity and accuracy. I'd agree that there is little reason to jettison what you have for the newer powder.
 
Welcome aboard.

Sounds like your 7828 load is a good one. Hard to beat it in a 7 Rem Mag.
 
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