Unkown Distance (UKD) Rapid Rifle Engagement, by JRS

This is a basic rifleman’s guide to rapid engagement on targets at unknown distances out to 500(ish) meters.

This approach is modeled on low powered variable optics, using mil based reticles and a 100m zero.

This is not meant as a mil relation article but hopefully you can start to pull the beauty of mils from it.

I will demonstrate the approach with a variety of ammunition.

My acceptable impact area is an IPSC “B/C” zone target.

The dimensions of the of this target are:

60 centimeters tall x 30 centimeters wide OR 23.62 inches wide x 11.8” inches wide

There is a relation, or three “math” things the shooter must grasp and put together to make the shot.

-Target Size, in mils at various ranges

-What is the bullets drop

-What is the target affording me to hastily make a snap call on range

So, lets math this real quick. Below is a mil relation chart showing the height of the target in mils at the various ranges. Understanding your desired area of impact, and its mil relation to range, tells the shooter how much “slop” he can get away with.

Range

Size in mils

275

2.2

100

6

300

2

125

4.8

325

1.8

150

4

350

1.7

175

3.4

375

1.6

200

3

400

1.5

225

2.7

425

1.4

250

2.4

450

1.3

Next we must understand what our round is doing at various ranges. These are all fairly generic rounds coming from a 14.5” rifle with a 100m zero. (This is all generated from Applied Ballistics)

14.5”

1:7 twist

2.5” Sight Height

100m Zero

Round

55gr Wolf Gold

IMI M855

Frontier 75gr BTHP

IMI 77gr SMK

62gr GDSP

Muzzle Vel

3030

2960

2615

2600

2589

100

0.0

0.0

0.0

0.0

0.0

125

0.0

0.0

0.0

0.0

0.0

150

0.1

0.1

0.1

0.1

0.1

175

0.1

0.1

0.3

0.3

0.3

200

0.2

0.3

0.5

0.5

0.5

225

0.4

0.4

0.7

0.7

0.8

250

0.6

0.6

0.9

0.9

1.0

275

0.9

0.8

1.2

1.2

1.3

300

1.1

1.1

1.5

1.5

1.6

325

1.4

1.3

1.8

1.8

2.0

350

1.7

1.6

2.1

2.1

2.3

375

2.0

1.8

2.4

2.4

2.7

400

2.3

2.1

2.7

2.7

3.1

425

2.7

2.4

3.1

3.1

3.5

450

3.0

2.7

3.5

3.5

3.9

Now lets compare the above chart, to chart relaying size:

The red highlighted cell indicates where the bullets drop, exceeds the target size. In lay mans terms, this means where you can no longer hold the top edge of the target and achieve a hit.

***Given a 14.5” barrel, a variety of commonly available rounds, and a desired impact area of 24” in height. You can get out to 300-350m just by holding the top edge of target with a 100m zero.***

B/C Zone Size

Round

55gr Wolf Gold

IMI M855

Frontier 75gr BTHP

IMI 77gr SMK

62gr GDSP

Muzzle Vel

3030

2960

2615

2600

2589

6

100

0.0

0.0

0.0

0.0

0.0

4.8

125

0.0

0.0

0.0

0.0

0.0

4

150

0.1

0.1

0.1

0.1

0.1

3.4

175

0.1

0.1

0.3

0.3

0.3

3

200

0.2

0.3

0.5

0.5

0.5

2.7

225

0.4

0.4

0.7

0.7

0.8

2.4

250

0.6

0.6

0.9

0.9

1.0

2.2

275

0.9

0.8

1.2

1.2

1.3

2

300

1.1

1.1

1.5

1.5

1.6

1.8

325

1.4

1.3

1.8

1.8

2.0

1.7

350

1.7

1.6

2.1

2.1

2.3

1.6

375

2.0

1.8

2.4

2.4

2.7

1.5

400

2.3

2.1

2.7

2.7

3.1

1.4

425

2.7

2.4

3.1

3.1

3.5

1.3

450

3.0

2.7

3.5

3.5

3.9

Now I am going to introduce hasty range guestimation using mils

There are two sizes to keep in mind. 12 inches and 20 inches.

Tgt

Mil Read

Range(m)

Tgt

Mil Read

Range(m)

20”

.9

564

12”

1.0

305

20”

1

508

12”

.9

339

20”

1.1

462

12”

.8

381

20”

1.2

423

12”

.7

435

20”

1.3

391

12”

.6

508

20”

1.4

363

12”

.5

610

20”

1.5

339

Realistic hasty milling of a target, with most 1-6/1-8/1-10 reticles I can mil targets to +/- .2 mils. Meaning I can tell the difference between 12” that mils at 1.0 and 12” that mils at .8.

***If you are engaging a target that is conducting proper individual movement techniques (3 to 5 seconds rushes) is it reasonable to expect to mil a part of him?***

***This is when it comes down to ammo choice. I personally use 75gr and 77gr loads. So going forward I will use that***

Now the shooter has to look at the relation and make the judgement on:

-Ease of milling the target (1.0ish is easier to read than .6ish)

-Target size (in mils) compared to bullet drop. (What can I hold, and still be inside the target?)

All that boils down to this, for using a 14.5” rifle and shooting 77gr SMK

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About the Author: NC Scout

NC Scout is the nom de guerre of a former Infantry Scout and Sergeant in one of the Army’s best Reconnaissance Units. He has combat tours in both Iraq and Afghanistan. He teaches a series of courses focusing on small unit skills rarely if ever taught anywhere else in the prepping and survival field, including his RTO Course which focuses on small unit communications. In his free time he is an avid hunter, bushcrafter, writer, long range shooter, prepper, amateur radio operator and Libertarian activist. He can be contacted at [email protected] or via his blog at brushbeater.wordpress.com .

6 Comments

  1. DAN III August 3, 2020 at 06:47

    An excellent article ! The information provided should help riflemen and potential riflemen to make their weapon combat effective.

    If American Patriot had a “Sticky” category I would ask this essay be at the top of the list.

  2. Anonymous August 3, 2020 at 08:29

    5

  3. Badlands Rifleman August 3, 2020 at 12:49

    That’s a good write up, definitely handy for those mil based reticles. I hate to sound rude but if you’re not looking at the ACSS reticles for a DMR or patrol rifle I think you’re wasting your time and ammo using something outdated and inferior. It’s not your typical generic BDC reticle from 20 years ago. I’m finding I prefer the speed and simplicity of the ACSS reticle, almost no math at all and it works great with a variety of rounds. I zeroed mine using 62 grain hollow point boattail 5.56 at 300 yards and the reticle has been dead on out to 500. I’ve also confirmed ballistics with M193 using the same zero and it’s still usable without rezeroing. After 500 yards every breath of wind knocks my rounds left or right, but elevation is usually pretty close out to about 700 yards.

  4. Anonymous August 3, 2020 at 14:49

    4.5

  5. Red in OleVirginny August 4, 2020 at 10:36

    “When we look at a target with our Mk1 eyeball and can see any kind of detail, that is a close target.
    Details would be stuff like gender, hair color, hair style, general type of clothing (e.g. wearing a jacket or not), other equipment (e.g. backpack, rifle) etc..
    With a close target, we will aim at the bellybutton, since generally the target will be within ~300 meters and our bullet will impact above the line of sight and thus somewhere on the torso.

    When we cannot make out any of those details and are just able to see a person, we have a far target.
    With a far target, we aim at the neck/head, since our bullet will impact below the line of sight – again, somewhere on the torso.
    The beauty of this is that we do not have to worry about the grey area between close and far targets.
    As we approach the end of close distance, our point of impact moves closer to our point of aim – we will still hit the hip or groin area.
    If we go to the far target hold too early, the bullet will not hit below our line of sight, but rather high on the torso or in the shoulder/head area – no big loss, is it?

    Basically, all we are doing is taking the Battlesight Zero concept and adding a single step of complexity: instead of always aiming at the center of a given target, we aim at the lower end of the target at close range and the higher end at long range.
    The shooting itself consists of two parts:
    The first shot is a carefully aimed single shot. If it hits and produces perceptible results, we can stop.
    If it does not produce results, be it from a miss or a bad hit, we change to what the Swiss call “rasches Einzelfeuer” – rapid semi-auto.

    Depending on our shooting position and distance, we shoot five shots at a steady rhythm of 1 to 2 rounds per second.
    We do not try to see bullet impact, we do not change our point of aim.

    Putting it all together, let´s say we perceive a possible target.
    As we establish our shooting position, we go through the very short check list.

    Do we see details? – No. FAR target, neck/head hold.

    Wind? – Just a touch on the face from the right side: WEAK, HALF a target´s width into the wind.

    At the time we are content with our shooting position, we already know that we need to aim just above the right shoulder of the target – the process took us mere seconds (and can be practiced any time you go out for a walk…).

    And that´s about it…with a combination of stuff we most likely knew already, we can now produce hits on targets at 500-600 meters with any type of reticle and without any adjustments on our scope. ”

    I have taught this method to new riflemen and women with good results. Hope this helps and adds something relevant to the conversation. I enjoy your blog.
    Best Regards
    Red in OleVirginny

    • Patriotman August 4, 2020 at 10:42

      This is a great addition! Thanks for sharing!

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