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Discussion Starter · #1 ·
When I was in the military, we were sighting-in M14s. (You can guess it was a while ago!) The method used was to put the target out a short distance from the firing line and shoot, adjusting the sights for shot grouping. When we were done, the rifle was sighted in at 100 yds. I don't remember what the short distance was so that the rifle would be sighted in at 100 yds. I'm sure there are other distances which could be used for other distances. Does anyone have the exact short distances from the firing line the target must be set at for it to be sighted-in at say, 100 yds., 200 yds. and 300 yds.? Trying to remember from about 50 years ago doesn't work too good! Appreciate any assistance.
 

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Discussion Starter · #4 ·
The M16A1s were intially zeroed at 25 yds in 1972. The POI was the same at 25 yds as at 100 yds. It could have been the same for the M14 since the military was on the KISS system.
Probably would be the same. The next time I get to the range, I'll have to try it by setting two targets, one a 25 and other at 100 yds. Sight in on the 25 and then see what the group is at 100. Thanks for in input.
 

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Discussion Starter · #6 ·
AR15.com has a thread with printable short range sight-in targets for common ar-variants.

http://www.ar15.com/mobile/topic.html?b=3&f=18&t=556355

If posting the link is taboo, please let me know.


ETA weapon type distinction
Wouldn't the whole sighting in process be based upon the caliber of the ammunition being fired? The bullet drop of the 5.56mm is different from the .308 which is different from the 8mm, etc. I would think the there would be a different set of distances for each type of ammunition?
 

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Absolutely. There are different targets on that site for m16-a2, m4, etc, depending on height of sight/scope above bore, length of barrel, type of ammo, etc. For any other cartridge/sight combination you would have to figure out new offsets for the targets. You could still use the same reduced range distances, but the POI at short distances would be different.
If you're good at math, you could figure out the probable trajectory. If, like me, you aren't able to figure how scope height above bore center will affect trajectory, you could use the ar target aiming points, make your best guess from a trajectory table, and then field test where that zero puts your POI at the ranges you want data for, sort of trial and error.
 

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Wouldn't the whole sighting in process be based upon the caliber of the ammunition being fired? The bullet drop of the 5.56mm is different from the .308 which is different from the 8mm, etc. I would think the there would be a different set of distances for each type of ammunition?
...which ALL need correcting for the distance the sightline is above the boreline as well.

I would be VERY surprised to find the two 'crossover points' between the sightline and the trajectory (which is what you need to have for short-range sighting in) at just about any distance for an M14 and an M16 to be the same.
 

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When I said 25 and 100 yds in post 3, I should have said meters. The US Army was already switching to metric. I recall they showed us a trajectory chart and pointed out that the POA and POI intersected at 25 and 100 meters. The POI was still rising after 100 meters but I can not recall the next range where they converged again. Of course this was 55 grain 109 ammo, factory iron sights, M16 and M16A1.
 

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Rifles are different and ammo is different, so their really is no-size-fits-all for sighting in very accurate rifles for precision shooting. Hornady and other ammo manufacturers have good on-line ballistic calculators that can predict bullet drop for making a starter dope card, but nothing beats really shooting with your own rifle and your chosen ammo.

Still, in a pinch you can do the old hunter's trick, setting the POI 2-4 inches high at 100 yards and figuring you can then shoot hunting size (or sniper size) targets point blank to 300 yards or so. This delivers the old Ohio hunter's "minute of pie plate" accuracy required to bring home dinner at normal hunting ranges.

A quick study of bullet drop from a bullet drop calculation will give you a rough idea for the "Kentucky windage" holdover to shoot a bit further than the 300 yards, estimating holdover for longer range. This has taken many deer for many hunters and has probably worked for many soldiers as well, bringing their woods skills to the jungles and steppes and cities they had to fight in.
 

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I have never had a rifle that was zeroed in @ 25 yard be zeroed @ 100 yards. I have zeroed many rifle and to have them approximately zeroed at 100 yards I shoot 1.5" to 2" low at 25 yards. depending on caliber and velocity of caliber I was zeroing.
 

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The M14 was zero'd at 25 meters for a battle sight zero. No guesses here, No assumptions.. That is what the US Army did. Went through basic training and this is how it was done.

Wow...I was taken aback here guys, you all are younger than I thought !
 

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The M14 was zero'd at 25 meters for a battle sight zero. No guesses here, No assumptions.. That is what the US Army did. Went through basic training and this is how it was done.

Wow...I was taken aback here guys, you all are younger than I thought !
Yea Skip, We both remember what we did in Basic and I am sure of what I am saying. I also remember I shot about 3 groups for zero and none of them were good enough for a correct zero. I was already a pretty good shot and was quite unhappy. I am thinking what is wrong with the rifle? Hey, I made ragged hole groups in boy scouts with the Mossbergs, plus I had my own rifle for 6 years and did not often miss. I could not afford to, a box of 22 LR was 85 cents. If I got a box every 6 mths I was doing well. The Range instructor took my rifle and tried himself. He also could not produce a tight enough group. Him and another drill sgt looked an each other and he handed it back to me and said, oh well, it is not you afterall and it is close enough. The dang POStuff was worn out yet I was stuck with it for record fire. It also was bad to double when on semi. As a result I ended up short of rounds on record fire as it would double about 10% of the time. They did not care, I was just one little cog in the wheel.
 

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Yes. I too trained in basic (Ft. Polk, 1967) with the m14. The zero was 25 yards. This was the "battle sighting". You were advised to aim at the enemy's belt buckle and would hit him somewhere out to about 400 yards. I qualified expert on the qualification targets following that advice.
 
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