I got an invite to go out to a field in the middle of Virginia and shoot rifles, so I thought I aught to do an OCW test to find some rounds appropriate for closer to a grand in my 308, just in case I ever get to shoot that far. My test didn't go as well as planned; or so I thought.
I settled on some of Alliant's sweet Reloader 15 powder as it's manufactured by beautiful angels in a temple made of goodness. It's also been around for like forever -- Adam and Eve used to use it when they shot F-class -- so the accuracy nodes are very well known. That saves me a lot of time. 43.1 grains of it seem to be a popular load; my only concern is that I'm not using Lake City brass, which is what that charge is used in.
I loaded three rounds each in 42.5; 42.8; 43.1; and 43.4 grains using brand new Winchester brass, CCI BR2 primers, and 175 grain Nolser Custom Competition bullets, seated at 2.227" to the ogive. I also loaded a bunch of other stuff to try out that I never got to shoot. I finally got to set up to shoot this test the evening before range day, which is not ideal.
I got all set up with my table at 104 yards, chrono up, Practical Riflery Forums official test target up, and settled in on shooting from lowest charged rounds to highest in round robin style. The first three rounds went well enough, and then the chronograph failed to catch the velocity from the first 43.4 charge, which prompted me to raise the tripod a bit so that the rounds fly a little closer to the timing lights. It was getting dark, which makes chronos give errors. Back around from the 42.5 charge and all is looking good, and then at the 2nd 43.1 and 43.4 charge the chrono didn't get the velocity. Up goes the tripod again, and then nothing. I raised it a little more and finished my shoot, firing the last charges one right after another, and noticed the very last round, the last 43.4 charge, hit about six inches low and almost sideways. This would be why:
Cutting it a bit close. It seems these things need sunlight or some shit to function properly.
I absolutely lost it.
My brother was walking up and asked me what was wrong, and unfortunately got to hear a ten minute, profanity laced, hundred-and-ten decible diatribe about how I would pay a billion dollars for one hour of perfection, absent people or distractions, so that I may actually get to participate in my silly hobby.
So now I have a target where my groups are tightening up nicely at 43.1, and at the next charge my round is keyholed because of a stupid chain of events, so it's a big assed guess as to what my decided charge should be.
Top left is 42.5; top middle 42.8; top right 43.1; and bottom left is 43.4. The shots from the test are circled with blue pen (43.4 charge only has two shots); the rest of the shots were the contents of a 20 round magazine that was promptly fired at that target in an un-scientific manner (There was a lot more target than you can see here, for those of you counting shot holes!).
Velocities were:
42.5 - 2,398, 2,402, error
42.8 - 2,455, 2,433, error
43.1 - 2,478, error, error
43.4 - error, error, OWWW!! WTF!!!
After some careful thought I gambled on 43.3 grains. The 43.1 and 43.4 were hitting tight from what I could see, and more importantly to the exact same point-of-aim, point-of-impact. Theoretically if all three 43.4 charges hit tight in the same manner as the 43.1, than my accuracy node may fall in between the there. I loaded fifty of them, as well as five each of 43.1 and 43.2, just to see what they would do, and headed off to shoot.
We got the targets set up at 100, 200, 250, 450, and 514 yards in this bean field:
I started at 100 yards over the chrono, and we had bluebird skies, so there was no excuse for the chrono this time. Temp was 79, wind was 5-10 for awhile, then still as can be in the afternoon. Couldn't ask for a better day for shooting! You people in the South West have to deal with all that wind, while us East Coasters only have to worry about the humidity.
Final velocitie were:
43.1 - 2,515, 2,501, 2,482, 2,501, 2,510
43.2 - 2,520, 2,534, 2,515, 2,496, 2,525
43.3 - 2,554, 2,534, 2,544, 2,539, 2,534
My sand bag setup left my hundred yard groups all over the place, so I fixed my rest and got down into the gun and fired a decent five shot group at 250 yards:
I was pretty happy with that. I can work with it. The target on the right is the 450 yard target, and I used a 2.8 Mil hold at last light with a scalding hot barrel to put a best four into 4.2". I almost didn't shoot it as my hands were shaking from not eating all day, and as I was pressing the trigger the reticle would wobble back and forth. I would guess it explains the horizontal stringing. The fifth round hit about five inches low, which I can't explain. It happens. I'm sure if I took my time I could tighten that up, but the vertical measure makes me hopeful.
On the 500 yard target, my first five shots with 3 Mils of hold over and .6 Mils right hit the top right target at the bottom. This was my first ever attempt at 500 yards with this rifle. Losing the wind call, and using 3.2 Mils hold later on got me four rounds centered on that middle target, but that was after ten rounds fired quick at balloons I had stapled onto the sides of the ply wood, as well as five rounds at the 450 yard target. The bottom shot was with the 3 Mil hold:
(Click to make bigger)
Not the tightest group, but I'll take it under the circumstances. Now I get to fine tune this round so that it shoots like I want it to. I'm also going to start a 69 grain SMK work up with Varget for my AR15 when I save up that billion dollars to buy some time.
I don't shoot so well when I'm rushed, which is pretty much all the time. This day at the range was very relaxed, which was great. Every day needs to be like this. I'm lucky I didn't destroy my chrono, as I've shot one accidentally before, and I seriously considered seeing what a 175 grain round would do to the LCD of this chrono after the test incident. Really though, you just have to have daylight and you're good. Hopefully I'll get to go back soon, and maybe I'll have my loads dialed in tight like they're supposed to be.
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