Range Day in the Snow.

[nosler06]

Well today I finally got out to the range. Had to walk through 14" of snow in some places. Temp was a nice -2.5*c, great for getting the barrel to cool down between groups. I have been playing with powder and seating depths with my old .308 Browning BLR for about a year now. I decided to try anouther set of load tests. Below are the results. I am still trying to decide on the 45.0gr, 45.5gr or the max load of 46.0gr Varget.

44.0gr Varget



44.5gr Varget



45.0gr Varget



45.5gr Varget



46.0gr Varget



They are not the best groups that I have shot, but the 45.0gr, 45.5gr and 46.0gr has promise to them. I just can't decide which one to go with.

 

[DrMike]

If velocity is acceptable, the 45.0 grain and 46.0 grain groups demonstrate virtually identical accuracy. You haven't much room to play with seating depth on the BLR, so you're working with velocity to tighten groups. I would be inclined to suggest looking at a different powder to tighten the groups. What you have is certainly acceptable, especially at normal field ranges; still, for confidence, I'd look at another powder and even another bullet to see what data you generate.

 

[SJB358]

Yeah, looking at your target, 45 grains looks pretty acceptable for hunting, but again, like Mike was saying, you don't have a bunch of room to work seating depth with the BLR.

Another powder you might look at is W748. I ran into the same issues when working with the 358 and 225's. Varget, AA2520, H4895 all shot decent, but nothing to write home about. Had some old W748 and bam, groups came together pretty decently.

Cartridge : .308 Win. (SAAMI)
Bullet : .308, 165, Nosler PART SP 16330
Useable Case Capaci: 48.677 grain H2O = 3.161 cm³
Cartridge O.A.L. L6: 2.800 inch = 71.12 mm
Barrel Length : 22.0 inch = 558.8 mm
Powder : Winchester 748

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 86 41.40 2518 2322 43670 7817 98.3 1.222
-09.0 87 41.86 2544 2371 45117 7887 98.5 1.204
-08.0 88 42.32 2570 2420 46613 7953 98.8 1.187
-07.0 89 42.78 2596 2469 48162 8016 99.0 1.170
-06.0 90 43.24 2622 2519 49763 8077 99.2 1.153
-05.0 90 43.70 2648 2569 51422 8133 99.4 1.137
-04.0 91 44.16 2674 2619 53138 8187 99.6 1.121
-03.0 92 44.62 2700 2670 54908 8236 99.7 1.105
-02.0 93 45.08 2725 2721 56732 8283 99.8 1.089 ! Near Maximum !
-01.0 94 45.54 2751 2772 58614 8325 99.9 1.074 ! Near Maximum !
+00.0 95 46.00 2776 2824 60560 8365 99.9 1.059 ! Near Maximum !
+01.0 96 46.46 2801 2875 62573 8400 100.0 1.044 ! Near Maximum !
+02.0 97 46.92 2827 2927 64657 8431 100.0 1.030 !DANGEROUS LOAD-DO NOT USE!
+03.0 98 47.38 2852 2979 66813 8460 100.0 1.016 !DANGEROUS LOAD-DO NOT USE!
+04.0 99 47.84 2877 3032 69047 8488 100.0 1.002 !DANGEROUS LOAD-DO NOT USE!
+05.0 100 48.30 2902 3085 71359 8516 100.0 0.988 !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 95 46.00 2877 3032 72757 7992 100.0 0.988 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 95 46.00 2626 2526 48907 8470 96.7 1.155

 

[nosler06]

When I was at the range I was talking to another guy who had a .308 there and he said he thought that the Varget was his end all answer, so he bought 8lbs. He told me that he has never been able to get his rifle to tighten groups like when he shot IMR3031. This BLR rifle of mine shot sub 1" groups when it was loaded with IMR4350. Maybe I should go back to the loads of IMR4350 and go with that. I am getting stumped with it. Also that I have sent $120 worth of Nosler Parts down range. I have tried IMR4895 and the target looked like a shot gun pattern. Absolutely no grouping at all with it. Availability of W748 where I live is a difficult issue. I wonder about IMR3031 or IMR4064. I do not have much experience or knowledge about Hodgdon BL-C2.

 

[DrMike]

IMR3031 and IMR4064 will each work well in the .308. Recently, I've worked up some loads with IMR8208XBR with excellent results.

 

[nosler06]

Mike, if you were to pick one of these powders to try first which would it be..IMR3031 or IMR4064? I shoot 165gr NP's from my .308. There is a bit of a spread as to burn rates. IMR3031 is a faster burning powder.

 

[DrMike]

I like both of those particular powders; they are old favourites. The burn rate is sufficiently close that velocities will be quite similar. Perhaps I lean more toward IMR4064, but not out of conviction that it is superior to IMR3031. If you have access to BL(C)2, give it a try. It is an excellent powder in that cartridge and with that bullet weight.

 

[SJB358]

I'd try 4064 first as well. 3031 would probably be better with the 150's speed wise. It's rifles like this that test us.

 

[Elkman]

Either, don't believe that either is more accurate than the other. My 08 likes, Varget, and RL-15 the best.

 

[nosler06]

Well I guess I will be leaning towards trying the IMR4064. If that does not work I will go back and play with the IMR4350 and try H4350 as well. Like I said the IMR4895 was worse than the Varget for any groupings. I might load some IMR4350 rounds anyways to run them thru as soo as I look up dad's old load data for the BLR .308.