Assistance zeroing Aimpoint T-1

[sapper091]

Hi fellow shooters,

I've set my ego aside and I'm now asking for help.
I'm having issue trying to zero my Aimpoint for 25 meters. Then when I think I'm close enough and shoot at 10-15 meters I'm no where on target.
Here's my current set up.

- Aimpoint T-1
- DD Mk18

Can anyone walk me talk me through with zeroing again?

Cheers!

[JulyAZ]

https://youtu.be/oHb4D2vavrM

[sapper091]

What’s your issue? You need to provide further info.

Are you zeroed at 25? And can’t hit at 10?


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Yes I was zeroed at 25 but when I brought in the target in to 10 I was no where on target. I was shooting low. Any idea why?

[bulldozer3]

Yes I was zeroed at 25 but when I brought in the target in to 10 I was no where on target. I was shooting low. Any idea why?

You should be low in that case... maybe an inch- dont recall exactly

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[JulyAZ]

Yes I was zeroed at 25 but when I brought in the target in to 10 I was no where on target. I was shooting low. Any idea why?

It will be low, bullets fly in a arching manner, they don’t fly straight. The closer you walk the target in at from 25 meters it should be more inline with the ejection point of the bullet leaving the barrel.

Jut learn your hold overs, and make a dope chart so you know where to aim at the given distance.

Think of the bullet as a football and not a laser.


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[Dr Dues]

It's called "offset", and depends on sight height over bore.

Depending on the mount, you should have close to 2.5" of bore offset (the distance from center bore to sight picture).

This is why it is important to learn your offset and change sight picture accordingly especially at close and near contact distances.

Their is alot of info. on offset here and on the web in gen.

[Joe R.]

Mechanical Offset is something you need to be familiar with. It's a fact of life with straight line stocks (like on your AR).

What that means it that the line of sight on your sighting system, be it irons or optics, sits above your line of bore. This means the line of bore is actually pointing in an upward angle and your bullet will intersect your line of sight at your zero distance. The round will then continue it's upward trajectory until it hits it's apogee, the round will then start to fall and eventually cross your line of sight again. With a 50 yard zero, which I highly recommend, this means your round will cross at approximately 200 yards.

What does all this mean for you? With a 50 yard zero at anything closer than 50 yards your rounds will hit low if you hold your "normal" zero. At 25 yards you will hit about 3/4-1" or so low. At 10 yards you will be about 1 1/2-2" low. At 5 yards you will be about 2 1/2" low. This is all dependent on optic, mount height, etc. What you need to do is learn your hold-overs. Do this by holding your dot on a spot on the target and seeing how low your impact point is. You will then need to hold that much higher to achieve a hit on your target. Even if you continue to use a 25 yard zero you will still need to take mechanical offset into account as you have already discovered. Also a zero closer than 50 yards has fairly dramatic effects at longer ranges as well. IE: a 25 yard zero will hit about 6-7" high at 100 yards...again dependent on ammo, optic, mount height etc.

Your best bet is to get to a basic carbine course that covers this and run the drills that demonstrate the issue. This picture will help illustrate what I have spelled out above.aimpoint zero.jpg

As I mentioned, different zero distances will have different effects on mechanical offset as illustrated below.
aimpoint various zeros.jpg

PS: Full Disclosure...I work for Aimpoint as a Prostaff member.

[sapper091]

Mechanical Offset is something you need to be familiar with. It's a fact of life with straight line stocks (like on your AR).

What that means it that the line of sight on your sighting system, be it irons or optics, sits above your line of bore. This means the line of bore is actually pointing in an upward angle and your bullet will intersect your line of sight at your zero distance. The round will then continue it's upward trajectory until it hits it's apogee, the round will then start to fall and eventually cross your line of sight again. With a 50 yard zero, which I highly recommend, this means your round will cross at approximately 200 yards.

What does all this mean for you? With a 50 yard zero at anything closer than 50 yards your rounds will hit low if you hold your "normal" zero. At 25 yards you will hit about 3/4-1" or so low. At 10 yards you will be about 1 1/2-2" low. At 5 yards you will be about 2 1/2" low. This is all dependent on optic, mount height, etc. What you need to do is learn your hold-overs. Do this by holding your dot on a spot on the target and seeing how low your impact point is. You will then need to hold that much higher to achieve a hit on your target. Even if you continue to use a 25 yard zero you will still need to take mechanical offset into account as you have already discovered. Also a zero closer than 50 yards has fairly dramatic effects at longer ranges as well. IE: a 25 yard zero will hit about 6-7" high at 100 yards...again dependent on ammo, optic, mount height etc.

Your best bet is to get to a basic carbine course that covers this and run the drills that demonstrate the issue. This picture will help illustrate what I have spelled out above.aimpoint zero.jpg

As I mentioned, different zero distances will have different effects on mechanical offset as illustrated below.
aimpoint various zeros.jpg

PS: Full Disclosure...I work for Aimpoint as a Prostaff member.

Much appreciated for taking your time and explaining this.
Cheers!