5/17/2010 - 500 Yards

It's nice to know that even when dealing with some wind, 4 great shots in a row are very possible.  Today I tested the new scope bases at 500 yards.  After I had the shot all set up, I realized I didn't have the bullet drop data with me.  I called Karen and had her look it up for me.  She indicated that at 500 yards with this setup, the chart said I needed 11 MOA in the scope.  Trusting that to be the case, I dialed 44 clicks of elevation.  Truth be known, I actually shot one shot and watched the dirt kick up about 5 feet low!  I then realized that you have to do more than the math on 11 MOA, you also have to dial it in!  After the scope adjustment, I was ready again.  There was a steady crosswind where I was shooting, but I couldn't see the grass moving at all over by the target.  I decided that I would hold the crosshairs on the right hand side of the cardboard to compensate for wind.  I tried as best as I could to get an idea of the shot placement based off of the dirt kicking up.  My best guess was that I was hitting a little high and to the left, but I decided to shoot 4 good shots at the same place and then walk over to see the results.  During my walk over, I fully anticipated to find that I had missed the target high and left.  Much to my surprise, it was 4 of the most consistent shots to date.  There was one grouping in late January that was possible better, but that was only 425 yards.  This is most definitely sub MOA.  It's about 1/2 MOA actually.  It measures just under 2 inches vertically, and just over 2 inches horizontally.  It amazes me that the data I am getting from those bullet drop calculations can get me this close.  Notice how accurate the elevation is.  I was shooting 175 gr. Black Hills Match 308 ammo.  I only wish that I didn't have any wind.  Had I been able to hold dead center (it's been since about January since I was able to do that), this might have been a really impressive picture!

5/7/10 20 MOA Scope Bases

Today my 20 MOA Nightforce Scope bases got a test run.  20 MOA bases point the scope downward in relationship to the bore. This gives you added elevation travel from the scope (since you really never need to adjust down, when you are zeroed at 100 yards). Overall, my Vortex Viper Scope has 258 clicks of elevation from the bottom to the top. This of course translates to 64.5 minutes of angle in elevation travel. Since at the factory, they make sure that the scope will be in the middle of it's elevation travel when held level, you really only get about 30-32 MOA of "up" elevation travel with a normal setup.

With the 20 MOA bases, it points the scope "down", meaning you need to compensate with the elevation knob to enable a zero at 100 yards. This is great because now after zeroing at 100 yards, this is what I have left for adjustments on the scope: 176 "up" clicks (44 MOA), and 82 "down" clicks (20.5 MOA). Since calculations seem to indicate that it will be around 36 or so MOA, to get the bullets in the vicinity at 1K yards, the rig is set up for the shots (more of less).

These pictures show that for whatever reason, I am not yet (with this current stock gun setup) claiming any better than 1 MOA at 100 yards. Interestingly enough, once I was sighted in with the 175 grain Black Hills Match ammo, I shot in the same basic place using my 168 grain hand-loads.

5/7/10 More for the Chrony Lovers

60 Degrees

8 Shots Black Hills Match 308 175 Grain BTHP

Low: 2584
High: 2645
Avg: 2613
Extreme Spread: 60.99
Standard Deviation: 20.07

10 Shots - 308 Win., 168 gr Sierra Match King, 42 Grains IMR 4064, Laupa Brass:

Low: 2567
High: 2633
Avg: 2588
Extreme Spread: 65.93
Standard Deviation: 18.73