Newbie AR Question [Archive] - Glock Talk

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Paul7
03-02-2010, 14:17
I've been shooting my new RRA A2 twice and both my son and I have noticed at the 70 yards we were shooting we did much better with the larger aperture rear sight, which seemed counter-intuitive. Is there any 'rule' of when to use the different rear sights or is it just a matter of personal preference?

CAR-AR-M16
03-02-2010, 15:56
The large A2 aperture is for 0-200 meters (should be marked "0-2" right below the aperture). The small aperture is for anything beyond 200. This link should help: http://www.armystudyguide.com/content/army_board_study_guide_topics/m16a2/zero-and-m16a2-rifle.shtml

kabob983
03-02-2010, 16:09
+1, the large aperature is used under 200 yards.

Also, learn your holdovers, it'll help you all around for adjusting for distance.

Paul7
03-02-2010, 17:37
The large A2 aperture is for 0-200 meters (should be marked "0-2" right below the aperture). The small aperture is for anything beyond 200. This link should help: http://www.armystudyguide.com/content/army_board_study_guide_topics/m16a2/zero-and-m16a2-rifle.shtml

Thank you. When zeroing it in, is it necessary to adjust the front sight or can it all be done making the two rear adjustments?

Kentak
03-02-2010, 21:18
It stands to reason that centering the front post in a small aperture is going to result in more precise aiming than doing so in a larger aperture. Hence, you need to use the small aperture for longer range shooting which is less forgiving of imprecise aiming.

So, why not use the small aperture all the time? Because it's not as quick to acquire the front post as it would with the larger aperture. So, you use the large aperture for shorter range shooting where the precision is good enough for general tactical use and where quick sight picture acquisition is more important.

Sound about right?

lawman800
03-03-2010, 00:34
Sounds good to me.

Novocaine
03-03-2010, 04:45
I use large apperture for low light only

Novocaine
03-03-2010, 04:50
Thank you. When zeroing it in, is it necessary to adjust the front sight or can it all be done making the two rear adjustments?

When you zero you adjust elevation with a front sight only.

Kentak
03-03-2010, 16:44
When you zero you adjust elevation with a front sight only.

True, but that assumes you first set the rear sight to the appropriate "zeroing" elevation, depending on your sight design and zeroing method you are using. Then, after zeroing, all further elevation (range) adjustments are made with the rear sight. (Unless I don't understand the question)

JCROWNII
03-13-2010, 20:46
I have a S&W M&P15X. Is this rifle zeroed out of the box? or does that even exist? if not, how do I know if my rifle is zeroed? does this mean point of aim is exactly the point of impact? I dont know how the hell to zero my AR. I have a troy industries BUIS as the rear sight and a standard M4/M16 front sight post.

Novocaine
03-13-2010, 23:13
I have a S&W M&P15X. Is this rifle zeroed out of the box? or does that even exist? if not, how do I know if my rifle is zeroed?

Why, shoot it.

does this mean point of aim is exactly the point of impact?

Yes. At certain distance. The most sensible is 50/200 yards range (bullet trajectory intersects the line of sight at 50 yards going up and at 200 yards going down). Itís known as Lt.Col. Santoseís method and places bullet trajectory within 2-3 inches (mostly within 2 inches) from point blank out to 250 yards.

I donít know how the hell to zero my AR. I have a troy industries BUIS as the rear sight and a standard M4/M16 front sight post.

Place your target at 50 yards. Flip the small aperture up. Fire a four-shot group. The point that is a geometric center of the group should coincide with your point of aim. If it doesn't adjust the sights, front for elevation, rear for windage. To adjust front sight is best to have a front sight tool. Rear can be adjusted with the coin/ screwdriver or a bullet tip.

To move the group up push the front sight down, to move the group to the left move the rear sight to the left. Confirm your zeroing at 200 yards.

Small and large apertures are on the same plane, your point of impact should not change when you flip between the two.

You can zero at other distances to your heart content but 50/200 method gives the best bang for the buck. Keep in mind, switching ammo or adding equipment to your rifle will likely affect the point of impact: might wanna recheck the zero. Good luck.

Alaskapopo
03-13-2010, 23:17
I use large apperture for low light only

It is good for low light but the large aperture is also much better for CQB. Its easier to shoot quickly with a larger rear aperture. Personally I use the large aperture out to 50 yards and then from 50 and beyond I use the small one.
Pat