Tell me if this sounds crazy...

[bigedp51]

Quickload software "estimate".
Bullet, Lyman 170 grain lead round nose w/gas check
3rd line in from the left, powder charge weight in grains
4th line, fps
6th line, chamber pressure in psi

Cartridge : .308 Win.
Bullet : .308, 170, LYM LRN GC 311291
Useable Case Capaci: 52.909 grain H2O = 3.435 cm³
Cartridge O.A.L. L6: 2.800 inch = 71.12 mm
Barrel Length : 24.0 inch = 609.6 mm
Powder : Vihtavuori N135

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 58 25.60 1527 896 10569 3969 81.8 2.508
-18.0 59 26.24 1565 941 11184 4126 83.2 2.451
-16.0 61 26.88 1604 988 11830 4282 84.7 2.395
-14.0 62 27.52 1642 1036 12507 4435 86.1 2.333
-12.0 64 28.16 1681 1085 13219 4587 87.4 2.269
-10.0 65 28.80 1719 1135 13965 4736 88.6 2.210
-08.0 67 29.44 1757 1186 14748 4882 89.8 2.152
-06.0 68 30.08 1795 1238 15569 5026 90.9 2.097
-04.0 69 30.72 1833 1291 16430 5165 92.0 2.044
-02.0 71 31.36 1871 1345 17334 5301 93.0 1.993
+00.0 72 32.00 1909 1400 18282 5433 93.9 1.943 (32 grains of N135 powder, 1909 fps, 18282 psi)
+02.0 74 32.64 1947 1456 19275 5561 94.8 1.896
+04.0 75 33.28 1984 1512 20317 5684 95.6 1.850
+06.0 77 33.92 2021 1569 21409 5802 96.3 1.806
+08.0 78 34.56 2058 1627 22556 5914 97.0 1.764
+10.0 80 35.20 2095 1685 23759 6022 97.6 1.722

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 72 32.00 2035 1591 22704 5542 99.0 1.772
Data for burning rate decreased by 10% relative to nominal value:
-Ba 72 32.00 1751 1177 14536 5000 84.2 2.160

Below is NOT your bullet or load, (.308, 208 grain, Hornady BTHP 30733) it is a photo to help you understand the above rows and columns. I did not want to have to upload another photo to photo bucket, its getting too full.

 

[Iceblood]

I think I'll start with 28 grns of n135 (milsurp brass), and look into picking up some red dot. One thing I've learned is that there is no "perfect" manual for the variety of powders and bullets I use; I have books by Lyman, Nosler, and Hornady and each is quite different from the last. From now on whenever a see a manual I'll buy it.

Thanks for taking the time to help me out!

 

[Andy]

The bullets you bought are not gas checked, but I assume you bought them lubed - had to ask.

You can go as high as 44.0 grs of N135 and be at safe pressures, but that bullet will lead badly at those pressures. I don't know that powder's characteristics, but it might not burn reliably at the 28.0 grs you suggested. Powders have a range of pressures in which they're designed to operate, and most medium fast powders like N135 typically operate best when the pressure is at least 35K psi and at that pressure that bullet will lead. Try it and report back.

You need to operate in the 20K psi and lower range, and shogun and fast pistol powders are best for that.

 

[Iceblood]

In case anyone is curious I went to the range today and fired 20 rounds of this stuff. My d!ck did not fall off, there is no leading in the bbl, and I didn't hit a thing. No discernable pattern at 25 yards. 30-34 grains may be better.

 

[fishx]

I would go around 36 grains at an OAL of 2.65 or 2.7