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tiistai 2. kesäkuuta 2015

Two weekends of long range shooting

May was a good month, as I had time to go to two different long range shooting areas.

The first one was in Hätilä, which is located near the city of Hämeenlinna. The shooting area is actually an anti-tank weapons range, where soldiers from Armored Brigade conduct their training.

The furthest distance to set targets was at 750 meters. Me and my buddy set our steel targets at 550 m and 750 m. We were using my .308 Tikka T3 and .223 AR-15. Wind was quite challenging, so it was a good training opportunity for us.

Here's some photos from Hätilä:

The shooting area in Hätilä and some targets.

Firing position.

View trough Vortex Recon R/T 15x50 monocular at 750 meters.

Target at 750 meters. Diameter is 50 cm.

Target at 550 m. Dimensions are 30 cm x 20 cm.

Our firing position.

My friend was using a shemagh as a shell catcher.

Fine precision rifles. Sako TRG's, Accuracy International AW's and AX's, Remington 700's, Tikka T3's, H&K MR338, Dragunov and some custom rifles.

The other shooting area was in Niinisalo, which is a training area of Pori Brigade. The range where we were shooting is normally used as a weapons testing range, mainly for artillery pieces.

I only have one photo of that day, as we weren't allowed to take photos of other people and their equipment.
We were shooting reactive targets, which were scattered at different distances between 530 m - 930 m. We trained how to shoot using shooting sticks and DIY wooden tripods, and how to shoot with the weapon canted sideways. We also practiced different shooting positions such as sitting, kneeling, standing and using your buddy as a support.

The shooting range in Niinisalo.


maanantai 11. toukokuuta 2015

Long range .22 LR shooting

I visited my parents this weekend and had a chance to shoot my father's old trusty rimfire rifle. It's an old Baikal Toz-17, made in Soviet Russia. I put a Pilad 4x32 "mildot" scope on it, using Sako Optilock bases and rings. I had some trouble zeroing it, as the dovetail wasn't centered over the rifle's receiver. Fine Russian craftmanship indeed!

After zeroing the rifle, I used a chronograph to measure  muzzle velocity. Then I added the velocity and bullet information to Applied Ballistics software on my tablet. After tapping in the atmospheric conditions, it gave out a range table.


The Pilad scope isn't a true mildot scope, as the dots aren't 1 mrad (mils) apart from eachother. In reality, they are 3 mrad apart. So I had to do little calculation the get the range table right for the scope.

I went out to a nearby field, where I set up a few 30 cm x 20 cm metal targets at ranges 100 m, 160 m and 210 m. 100 meters was easy, first shot hit. 160 meters was bit more difficult, my wind call was a bit off, so after correction I got a second shot hit. 210 meters was quite hard, as the magnification of the scope wasn't high enough to see splashes at that range on muddy ground. I got a few lucky hits, but nothing consistent.


The ammunition I was using was Remington Thunderbolt, which isn't the best choice for long range shooting. That's because it's muzzle velocity is supersonic, which causes it to fly at transsonic speed at one point, which lowers accuracy at longer ranges.
But shooting the Baikal was fun, it made me start planning on building my own long range rimfire rifle. Cheap to shoot and good training.

maanantai 27. huhtikuuta 2015

Bubble level and angle cosine indicator for long range shooting

To be more consistent with long range shots, deleting small errors is the key. I've participated a few sniper competitions and what I have learned from them, is that when adrenaline is pumping and there's a tight time limit for taking your shot, it's easy to cant your rifle. As a rule of thumb, 1° cant will move your point of impact 0,02 mrad for every 100 meters.
So, if cant your rifle 4°, and the target is at 800 meters, you'll miss by 4 * 0,02 mrad * 8 = 0,64 mrad. From the center of the target 0,64 mrad at 800 meter is a miss by 0,512 meters. For a human size target, what is most commonly used in competitions, thats clearly too much.
Here's a good article about cant: http://www.riflescopelevel.com/cant_errors.html

A solution for cant problems is a bubble level for your scope. Here you can see a bubble level combined with an angle cosine indicator.

 
Angle cosine indicator is used for shots that are pointed upwards or downwards. As an example, if you are shooting uphill and your slant range to target is 400 meters, it's not the range you should use for your elevation correction. As strange as it sounds, you would miss high of your target. Here's an "Improved Rifleman's Rule", which is simple and accurate enough for use in the field.
  1. Measure the inclination angle of the target above or below the horizontal direction.
  2. Measure the slant range distance to the target.
  3. Take the Bullet Path (or come-up or come-down) from the level trajectory at a horizontal distance equal to the slant range distance, and multiply that parameter by the cosine of the inclination angle.
  4. Use the result of this calculation to adjust the aim of the gun at the inclined target.
So using the ACI, you get a cosine of 0,8 for the inclination angle. For my rifle and cartridge, elevation for 400 meters is roughly 2,4 mrad. The get the hold for a shot uphill, I must hold 0,8 * 2,4 mrad = 1,92 mrad.
There are other methods too for figuring out holds for inclined fire, here's a good article about that.
http://www.exteriorballistics.com/ebexplained/article1.html

Here I'm setting up the bubble level. This is the first phase, getting it roughly level with the scope. For fine tuning, you should hang a 1 inch or thicker rope with a weight at 100 meters or so, to get it to point directly to ground. Then with good sand bag support, align your scopes vertical line to the rope. When the vertical line follows the rope nicely, check your bubble level. If it isn't level, loosen the screws and adjust.