The 7.62 x 39 is a low pressure round. 50K CUP and 45K PSI according to SAAMI.

https://saami.org/wp-content/upload...CFR-Approved-2015-12-14-Posting-Copy.pdf

Most load data that lists pressure in PSI is at 50-51K PSI. duno why.

You are loading for a bolt action, not a weaker AR-AK-SKS type weapon. I would not hesitate to bring the pressure up to at least 55K PSI and maybe even higher to 60K.

This might be tough to do with 335 as you would have to start compressing it. Ball powders sometime do not compress well.

Code
 Cartridge          : 7.62 x 39 (M43) Russ.
Bullet             : .310, 123, Hornady SP 3140
Cartridge O.A.L. L6: 2.190 inch or 55.63 mm
Barrel Length      : 18.0 inch or 457.2 mm
Powder             : Hodgdon H335

Predicted data by increasing and decreasing the given charge,
incremented in steps of 2.0% 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

-20.0   80    25.20   1856     940   21702   4398     74.5    1.326
-18.0   82    25.83   1903     989   23099   4573     76.0    1.291
-16.0   84    26.46   1952    1040   24595   4749     77.5    1.257
-14.0   86    27.09   2000    1093   26198   4923     79.0    1.224
-12.0   88    27.72   2050    1147   27918   5096     80.5    1.191
-10.0   90    28.35   2099    1204   29763   5267     81.9    1.160
-08.0   92    28.98   2150    1262   31745   5435     83.3    1.129
-06.0   93    29.61   2200    1322   33876   5600     84.7    1.098
-04.0   95    30.24   2252    1385   36150   5762     86.0    1.068
-02.0   97    30.87   2303    1449   38644   5919     87.3    1.039
+00.0   99    31.50   2355    1515   41314   6071     88.6    1.008
+02.0  101    32.13   2407    1583   44203   6218     89.8    0.978  ! Near Maximum !
+04.0  103    32.76   2460    1653   47331   6359     90.9    0.950  ! Near Maximum !
+06.0  105    33.39   2513    1725   50724   6493     92.0    0.922  ! Near Maximum !
+08.0  107    34.02   2567    1799   54415   6619     93.0    0.895  !DANGEROUS LOAD-DO NOT USE!
+10.0  109    34.65   2620    1875   58435   6737     94.0    0.869  !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     99    31.50   2509    1720   49645   6365     95.5    0.929  ! Near Maximum !
Data for burning rate decreased by 10% relative to nominal value:
-Ba     99    31.50   2171    1287   33974   5510     78.6    1.102

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