QuoteSituation: It is dawn (6am), and you successfully engaged a target directly to the west of your location at 200 yards with your M1 Garand. You switched rifles and shot until you ran out of ammo with your ar-15. It is now noon and you observed a man-sized target in the distance to the north. This target measures slightly less than half the width of your Garand front sight post and is located on 30 degree slope downward. The sun is directly overhead and the temperature has increased 25 degrees. You observe the wind is approximately 15 miles per hour traveling from the northwest to the southeast.
You have one round left for your Garand. Calculate your firing solution & show your work.
Can you do this?
Can you do it without a cheat-sheet?
Can you teach it with simplicity and precision?
Even if you
can do this on the back of a napkin, come join us in July!
We're excited to offer a
Known Distance Instructor Boot Camp on July 9-10, 2016! This event is designed to help enable instructors to plan, prepare, and execute a safe & effective KD clinic. Also, this clinic will help Shoot Bosses and Red Hats polish and perfect their KD presentations given at every 25m event. This clinic should help prepare Red Hats and SBs for the responsibility / privilege of running a KD as a dSB.
Click here to sign up: Known Distance IBC (http://appleseedinfo.org/search-states-location.php?locationid=556&id_event=4629)
Details:1. Prerequisites: Students at this class must be currently active Appleseed Instructors (Red Hat or above). Waivers for IITs to attend will be considered on a case-by-case & space available basis. Send a note if you need a waiver. We don't want any spot to go empty.
2. Because this is a non-shooting event, we're hosting it at Double Tap in Calera, AL. We'll have access to low-cost, comfortable bunk houses and the classroom as long as we want to work. The classroom and bunkhouses are climate controlled in July. We can pot-luck & grill out for Saturday evening meal.
3. Like many other IBCs, this will be in small group format to maximize participation in practical exercises. Lecture is boring! :-)
4. Topics we will cover include:
- Finding an acceptable KD location and negotiating for its use
- Differences in pre-event checklists KD vs. 25 meter event
- Choosing an appropriate range layout (fixed target line, fixed firing line, multiple target & firing lines)
- COF strategy to support event goals
- Pit operations
- Line Bossing a moving firing line
- Small group exercise: Teaching Three Tasks of a Rifleman
- Small group exercise: Milliradians made easy (a different I-M-C)
- Small group exercise: Trajectory and range estimation using MOA and Mil-dot methods
- Small group exercise: Strategy to shoot the AQT (BSZ vs. come-ups)
- Small group exercise: Troubleshooting line errors at a KD
- Small group exercise: Environmental effects
- Conducting live range estimation and target detection exercises
- Conducting an unknown distance exercise
Contact me or Rusty with questions.
Interesting that nobody has presented a solution.
Here's mine
Set distance at 575 yards (500 yds + 3 clicks). And holdover 4.5 MOA to the left for wind. Which is a line of white to the left of the target.
At slightly less than half the width of the front sight that is 3 moa / 20 inch (silhouette size 20 inches and front sight size 7.5 MOA)
=667 yds * .87 (cosine of shooting on 30 degree slope which is probably the angle of repose for the geographic feature)= 579 yds.
Hold over 4.5 MOA to the left to correct for wind and spin drift. For flat based .30 cal bullets I use 1 MOA per 10 MPH of wind * distance=
.75*667= 5 MOA-0.5 MOA for the spin drift at 500 yds (approximation)= 4.5MOA.
3/14/2016 Sorry, forgot to add that the 15 mph wind is 1/2 value wind; hence, the .75.
Unlike distance correction that you have to use the cosine for due to the effect of gravity, the wind effect is over the linear distance.
Other factors to consider are 25 degree increase in temp. That's OK because my rifles are all zeroed at 85 degrees and it wasn't zeroed in the morning.
The sun overhead sharpens the appearance of the target and may cause glare on the front sight.
No need to correct for coriolis effect at this distance
Helga is my M1 Garand. She is a Danish return with a VAR barrel and NM parts. She has a synthetic stock with a built in cheek piece and is 1 MOA with HXP ammo.