Why are Ballistics Important?

Each week we head out to the range and shoot at distances ranging from 300m to 800m. We're expected to be on target first shot at every range.

So how do we do it?

Experience is the way it has traditionally worked. When you've been doing it almost every week for 50 years it becomes second nature. Many of us aren't blessed with 50+ years of long range experience though which is why the modern ballistics programs are so useful.

There are two main factors for determining a bullets flight path and that is it's Ballistic Coefficient (BC) and it's velocity.

BC's are typically published by the bullet manufacturers. Velocity is measured with a chronograph or estimated by playing with the numbers until the ballistics program output matches up with some known results.

Understanding how a ballistics program works is too big a topic for a humble club website. If you are interested though the best place to start is Sierra's Exterior Ballistics Web Site. There's enough info there to write your own ballistics program ;-)

.223 Ballistics

Elevations Table:

0.224 80 grain Sierra Match King with 25 grains of AR 2208 26" barrel Velocity Approx 2950 ft/s

Amounts in Minutes of angle (MOA)

TO
Scope Setting Range 100m 200m 300m 400m 500m 600m 700m 800m 900m 1000m
F
R
O
M
  100m   1.8 4.4 7.5 11.0 15.2 20.0 25.7 32.4 40.3
  200m -1.8   2.6 5.6 9.2 13.3 18.2 23.9 30.6 38.5
  300m -4.4 -2.6   3.1 6.6 10.8 15.6 21.3 28.0 35.9
  400m -7.5 -5.6 -3.1   3.6 7.7 12.6 18.3 25.0 32.9
  500m -11.0 -9.2 -6.6 -3.6   4.1 9.0 14.7 21.4 29.3
  600m -15.2 -13.3 -10.8 -7.7 -4.1   4.8 10.5 17.3 25.2
  700m -20.0 -18.2 -15.6 -12.6 -9.0 -4.8   5.7 12.4 20.3
  800m -25.7 -23.9 -21.3 -18.3 -14.7 -10.5 -5.7   6.7 14.6
  900m -32.4 -30.6 -28.0 -25.0 -21.4 -17.3 -12.4 -6.7   7.9
  1000m -40.3 -38.5 -35.9 -32.9 -29.3 -25.2 -20.3 -14.6 -7.9  

Download 223 Ballistics Table

 

.308 Ballistics

Elevations Table:

0.308 155 grain Dyer HBC with 46 grains of AR 2208 26" barrel Velocity Approx 2900 ft/s

Amounts in Minutes of angle (MOA)

TO
Scope Setting Range 100m 200m 300m 400m 500m 600m 700m 800m 900m 1000m
F
R
O
M
  100m   1.9 4.5 7.6 11.1 15.2 19.8 25.2 31.4 38.5
  200m -1.9   2.6 5.7 9.2 13.3 18.0 23.3 29.5 36.6
  300m -4.5 -2.6   3.1 6.6 10.7 15.3 20.7 26.9 34.0
  400m -7.6 -5.7 -3.1   3.5 7.6 12.3 17.6 23.8 30.9
  500m -11.1 -9.2 -6.6 -3.5   4.1 8.7 14.1 20.2 27.4
  600m -15.2 -13.3 -10.7 -7.6 -4.1   4.7 10.0 16.2 23.3
  700m -19.8 -18.0 -15.3 -12.3 -8.7 -4.7   5.4 11.5 18.7
  800m -25.2 -23.3 -20.7 -17.6 -14.1 -10.0 -5.4   6.2 13.3
  900m -31.4 -29.5 -26.9 -23.8 -20.2 -16.2 -11.5 -6.2   7.1
  1000m -38.5 -36.6 -34.0 -30.9 -27.4 -23.3 -18.7 -13.3 -7.1  

Download 308 Ballistics Table

 

Using the Elevation Table

Example 1 : First time out at 700m with your rifle which is sighted in 1" high at 100m. The target is big enough to ignore that 1" high at 100 setting so just treat it as though it's dead on at 100m. In the from section go to the 100m line on the table.

The target is at 700m so go to the 700m column for a value of 19.8 minutes. You need to adjust the scope up nearly 20 minutes. For a 1/4 MOA scope that nearly 80 clicks that you need to go up. When you go out and shoot write your final setting on the table.

 

Example 2 : You come out the following week. This time out it's at 400m and your rifle is still set for 700m. In the from section go to the 700m line on the table. Now work your way to the 400m column for a value of -12.3 minutes. You need to adjust the scope down nearly 12 minutes. For a 1/4 MOA scope that nearly 48clicks that you need to go down. When you go out and shoot write your final setting on the table.

Windage Tables

The windage tables for the .308 155 grain Dyer HB and .223 Sierra Match King loads shown above are similar enough that we really only need one table to cover both.

Bankstown Chatswood have Windage charts drawn up for each range from 300m to 800m and they act as coach sheets during grade shoots because they contain graduated images for the targets.

Download Coach Sheets

300m

300m coach sheet

400m

400m coach sheet

500m

500m coach sheet

600m

600m coach sheet

700m

700m coach sheet

800m

800m coach sheet

Wind flag showing 10 mph

Wind flag showing 10 mph

Using the Windage Table

Example 1 : You're shooting at 800m you have your elevation from the elevation tables. The wind is from 2 O'Clock (2:00) and the flag is as shown on the right.

Comparing the appearance of the flag with the flag diagrams gives you an estimation of 10mph for wind.

Looking at the table for an 10 mph wind from the 2:00 direction you adjust 7.4 minutes right. That is approximately 29 clicks on a 1/4 MOA scope.