Sighting In Confusion

cueball961

I have a question about sighting in for two weapons, a Stag Arms AR-15 and a Springfield Armory M1-A scout rife. Both are equipped with the standard military sights, and I also intend to equip both with Aimpoint sights as well. Should I zero the Aimpoint at the usual battle distance of the iron sights or set them at a closer range?

CaptainAhab

Completely depends on your usage. I set all of my rifles to a first zero that gives me the smallest error at the greatest EXTENT of range. That is a LOT of variables. Example: I set my Rem700, .30-06 to 40yd first zero. This gives me 2" +\- out to 220+ yds, with second zero at about 180yds. Fits my use. May not fit yours.

bruchi

Okay, my 2 cents, the AR AFAIK for a BATTLE ZERO with irons you set it at 25 yards and you will hit centermass out to 200-300 yards, for farther out then you compensate with the rear sight.

Was told once that from that platform a 223 round will hit at the same elevation both at 25 yards and 250 and in between the amount of variance will be small enough to still hit where it counts in battle.

The AR, those I use for 3 gun matches I zero at 100 yards as that will shoot on average about 4 inches low at 25 yards, easier to compensate for 4 inches at a closer distance than farther out. No idea on the ballistics of your 308 but seems to me that 100 yards is a good place to zero most long guns and to compensate from there regardless of the sighting instrument one uses outside from very specific uses.

Think I read once here that Pegasus sets his 1000 yard zero rig at that distance, hopefully he will chime in here soon.

CaptainAhab

It looks like a .308 set to only have 1 zero, has to be set around 80 yds. Puts you at -4.15 at 200yds. Lots of variables there, of course.

JasonMPD

Assuming you are zeroing with off-the-shelf military spec ammo:

AMMO: 5.56x45mm SS109, 62gr FMJBT (0.331 G1 BC), 3100 fps
WEAPON: Mil-Spec AR15, 2.5" iron sight mechanical offset

Zero Distance = 25yrds

0yds: -2.5"
25yds: +0.0"
50yds: +2.3"
100yds: +6.0"
200yds: +10.1"
225yds: +10.4" (zenith)
300yds: +8.7"
400yds: +0.6" (basically back to zero)

In this case, though, given a "vital target area" of approx 16" in diameter (from the neck to the belt line, roughly), your maximum point blank range under ideal conditions is approximately 500 yards.

AMMO: 7.62NATO, 147gr FMJBT (0.418 G1 BC), 2800 fps
WEAPON: M14/M1A, 1.1" iron sight mechanical offset

Zero Distance = 25yrds

0yds: -1.1"
25yds: +0.0"
50yds: +0.8"
100yds: +1.5"
175yds: +0.1" (basically back to zero)

So, with the sight height of a M1A, a 25 yard zero is pretty impractical.

Zero Distance = 15 yards (don't know if the sights make this possible...)

0yds: -1.1"
50yds: +2.2"
100yds: +4.2"
150yds: +5.0"
200yds: +4.3"
275yds: +0.6"
300yds: -1.8"
400yds: -15.3" (yikes!)

This is probably a lot of superfluous info you didn't need, but it might help in deciding where you want to zero your guns. If just for defense/plinking, a battle zero might be appropriate, but as you can see with how fast .308 nods off down range, you may want to consider a longer zero for the M1A if you plan to stretch its legs.

snake284

cueball961 wrote: »

I have a question about sighting in for two weapons, a Stag Arms AR-15 and a Springfield Armory M1-A scout rife. Both are equipped with the standard military sights, and I also intend to equip both with Aimpoint sights as well. Should I zero the Aimpoint at the usual battle distance of the iron sights or set them at a closer range?

Depends on what you're shooting at. If you want to shoot hogs at night at 100+ yards then you most asuredly need to sight it in for 100+yards. If you're going to shoot flies off a salt lick at 25 yards then sight it in at 25 yards.

sarg1c

Here at home, most shooters agree that 200 yd zero is easier to adj. to a 100 or 300 yd. hit than to have a 100yd. zero and try 200yd. hit. I agree .Still a lot of people like the 100yd. zero. The army still zero at 26meters as someone stated earlier, during battle it will give a better hit zone at various yrd age.Because where I hunt most deer are killed at 75-100 yds, I zero my Rem.700 (.308) at 100 yds. being hilly country. my .204 of course i'll zero at 200. It still a matter of what people like...

breamfisher

What do you plan on using the rifles for? That would let us know what distance to sight in at.

I keep my AR for plinking and for some home defense. My zero is set for 50 yds. for both the irons and the red dot. The 50 yd. zero extends the battle sight out slightly and gives me a good usable range.

cueball961

I remember in the Marines, we kept our 300 yard dope on our weapon as its "battle zero." Both weapons are going to be used for home defense, but the Mi-A may be pressed into double duty as a deer gun. My thinking was to possibly sight in the iron sights at ,say, 200 yards on both rifles, and then sight in the aimpoints at a close range for the defense work, maybe 50 yards. I'm an old school Marine, so I'm just not used to the aimpoint sights. Hell, not to date myself, but my issue M-16 had a three prong flash supressor, if that tells you anything!