C7 Zeroing from the 100m with a 300m elevation setting? Why?

[MJP]

TCBF's method of boresighting the 25mm chaingun:

1.   Dont.
2.   Pretend you are to avoid over-zealous AAA grads (Advanced Armoured Arseholes) from harrrassing you.
3.   Fire the zeroing practice.   Amaze others with how close your 'boresight' was to reality, vice theirs.

Tom

Hey did you copy from me.....funny how my first zeroing round always splashes in front of the target and the rest magically hit.

 

[48Highlander]

Ahh,

I love it when the trigger guys come out to play, NOT.

For starters, those of us who are SHOOTERS, and employed as shooters sight our weapons at in accordance with the 300 m setting.

I don't think I will explain it here, but those who have been employed as trunk monkeys, shooters and the like know why.

Suffice to say the initial zero is done at 25 m using a sighting targert.   Once the sights have been dialed in.   We go back to the 100 and confirm.   After that it is run ups from the 100, 50, 25, 15 and 5 m lines.

Most shooting is done within the 25 m box and around 300 m.

Ahhh, it's a special-forces-sniper-ninja-commando thing is it?  Well then, I'm sure we all apologize for speaking when we obviously have no idea what we're doing.  Forgive us oh mighty Shooter.

 

[KevinB]

Thats funy.  Yeah I know some who advocate a 25m zero for a C8 for CQB -- but a CAG buddy gave a very good rational for 100m zero.

Ideally you will have a chance to shoot your weapon from 5-600m and get a known POI - and if you have a scope that can (S&B SHort Dot or some of the other combat variables) you can get real zero's at all those ranges.

5,10,25,50,75,100,150,200,250,300,350,400,450,500,550,600 - Ideally you should know you POI's with a given POA --- however if you have a dedicated zero at 100m - save the paper take it in your weapons case (or weapons bag if your a downtrodden soul) - when you zero to adjust your weapon for the atmospheric/temp/pressure alt chnages at 100m - you will then still know where your rounds go at other ranges.  With a 25m zero you had best be one holing - but it will be hard to guarantee your zero is bag on for your dealing in 1/4MOA shift vice 1 MOA and consequentially doing 4MOA shifts.

If you are a C8CQB/EOTECH shooter the same principle applies -- just use a 50M POI/POA zero -- but still confirm at the 100m point (the 50m IBSZ - will give a +/-2" 50-250M fligth path with a 14.5" C8 and a 4" +/- for fligth path with the 10" C8CQB.  Same theory.

From a paper I got from then CWO(3) Mike Haugen the (then) S7 for 1 SFG(Abn)

B. Accuracy. It is generally believed throughout the SOF community that the M4 and 5.56 are not overly accurate at ranges past 300 meters. This “belief† has been supported by routine training at ranges below 300 meters, more commonly less than 50 meters.

1) Cause of issue: The cause of this particular issue stems from the same place, as does lethality, however examples of poor accuracy are even harder to obtain. The most common heard/red comment is generally how inaccurate 5.56mm generally is or more specifically how inaccurate M855 specifically is.

2) Reality. Perception can be turned to reality if untested and repeated.

†¢ M855 has an acceptance standard of 4 minutes of angle (4 inches @ 100 yards, 8 inches @ 200 yards, etc.).
†¢ M855 is a three-part bullet comprised of a steel penetrator, lead sleeve and a copper jacket. This design is inherently inaccurate due to the positioning of the penetrator.
†¢ Over 80% of SF marksmanship training is conducted at ranges less than 50 meters. On some teams this may not be the norm, however on most due to range availability and an increased emphasis on close quarters / urban combat training, long-range marksmanship training is not a priority.
†¢ Human sized targets out to and including 600 meters can be easily engaged with M855 if the soldier is trained.

 

[Gayson]

Maybe the coaches had the idea that it would be easier to hit targets at the 300m line, if the rifle was zeroed at 300m?

???

 

[Mineguy]

Just my 2 cents on zeroing...I did some "competetion" shooting with mr. cunnigham of the RCR who im sure some of you know. Did this back in the 90s. We zeroed our weapons as kevin b points out at all ranges but with the "open gate method". We zeroed at 100m and then with the adjustment gate lock under the elevation wheel always up we marked off the increment and liquid papered the square of the increment for 100m At all other ranges it was marked off (or paint scratched off the increment square) the same as going by the clicks on the main wheel wasnt so accurate because each sight was manufactured slightly diffrent. Now bear in mind this was the first generation sight from elcan. I used this method ther whole time i was in the army after and i always did well on the range with POI where i thought it would be and expected as per the little figure 11 targets pocket books we carried with all the details for each range 100-600 some of you may know about from using them. Also the kentucky windage worked well when using the flag position and judging wind. I would have liked to learn how to read the mirage from him. I have a couple of freinds who served in Rhodesia and they needed to use that there at times in the heat. We also used the saftey on drill (squeezing 9 times on the trigger hard as we could in the aim in a proper shot sequence, then on the 10th taking off the saftey and doing a proper shot with shot relase and folowthrough )to get the exact trigger pressure dwn which works acceptinally. Mr. Cunnigham does the mental marksmanship lecture which is worth hearing and definitly works, i still use it in other parts of my life to hit the target as intended when i want to do well!...to note for a 2000 3 RCR (bosnia training) section competetion i showed this to an Engineer team I was on and many of the other skills he taught us and we had some of the top shooting scores and thats a new one for engineers who are never usually on the rnage much, well at least in my time!..i was taught on my small arms coach course (ran by 2RCR sniper 1994) that the first setting of  was for all 1-2 hundred meters applications and that the second closed gate setting on the big wheel was 300 and onwards....