ACOG close in zero

[dragon7]

I have a new ACOG TA31H-G that I have sighted in at 25 to 100yds at a local rifle range. I'm not allowed to set up targets closer than 25yds at this range nor shoot my rifle on the pistol range. So my question is will my POI be much different at say 7 to 15 yds from my 25 yd. POI.

[chowchilla]

OK, maybe I'm wrong, but why do u need sights to shoot 7-17 yards???? that sight is meant for reaching out and touching something at 100+ yards...

[SuperSet]

I have a new ACOG TA31H-G that I have sighted in at 25 to 100yds at a local rifle range. I'm not allowed to set up targets closer than 25yds at this range nor shoot my rifle on the pistol range. So my question is will my POI be much different at say 7 to 15 yds from my 25 yd. POI.

At those ranges, your POI will be within your height over bore (~2.5").

[HK Dave]

OK, maybe I'm wrong, but why do u need sights to shoot 7-17 yards???? that sight is meant for reaching out and touching something at 100+ yards...

+1

I don't understand WHY this matters? The ACOG with your reticle was designed to be sighted in at 100 yards.

[dragon7]

With the ACOGs illuminated center reticle (in my case the horseshoe) it can and is used much like a nonmagnified RDS is used for CQB.

[HK Dave]

Hmm perhaps it was the "I have sighted in at 25 to 100yds" that is confusing us.

Yes at close range if you are zeroed at 100 yards... POI will be height over bore as SuperSet said.

[d4v0s]

If you sight in the rifle at 100 yards your going to most likely be 1 inch low at 25 yards, and 1.5-2.5 inches low at 0-17 yards.

The bullet is still rising to meet the ACOG reticle at 100 yards. In my non scientific testing, when I sight in my rifles for 100 yards, its usually 3/4 inch low at 25 yards. (I think my nikon 1-4 m223 has a lower mount than acog) BUT!!!! I never shoot groups that close its always steel or 8inch paper plates and in a run and gun format.

So what is it that your sniping at 17yards?

[ExtremeX]

I know... its not a TA31H, but the same should apply... Everything should be done in meters, you would need to figure out what the the actual POI at 25 yards from a 100 meter zero.

You should also be shooting the correct ammo the ACOG was designed for. 62gr M855... If are you shooting at an indoor range where that ammo isnt allowed, then XM193 will get you close, but you would have to take it to 100 meters and fine tune.

Anything except a 100 meter zero is going to jack up the BDC.

[ExtremeX]

On another note.... You have an ACOG, with a Horseshoe reticle... Its a combat optic, most people don't concern themselves with their 7-15 yard POI. In CQB distances on a man sized target just make sure the circle of death is on center mass and dump on it.

All the questions you have about POI can be answered if you get a ballistic drop chart for the ammo you are using with the correct parameters for your rifle.

[dragon7]

All extremely helpful info gentlemen. I can always count on CG contributors to give great info and constructive criticism. Love my new ACOG. Especially liking the green horseshoe center reticle I think it's genius. I regret waiting so long to mount one on my AR. My "close in" targets are going to be those cardboard humanoid guys with perforated lines on their chests. Trying to put one in the head can be dicey if my POI is above or below the hoseshoe. So it's good info to know ahead of time where the holes wil show up.

[Press Check]

You should also be shooting the correct ammo the ACOG was designed for. 62gr M855... If are you shooting at an indoor range where that ammo isnt allowed, then XM193 will get you close, but you would have to take it to 100 meters and fine tune.

Actually, the TA31 series is calibrated for a 55gr bullet / M193, not 62gr / M855. The TA01NSN is calibrated for the 62gr / M855 bullet.

[ExtremeX]

Actually, the TA31 series is calibrated for a 55gr bullet / M193, not 62gr / M855. The TA01NSN is calibrated for the 62gr / M855 bullet.

You might want to double check that for yourself.

I thought the same thing, until I called Trijicon few weeks back and asked them myself after buying a TA31F... The reason I called is there is conflicting information on the Internet. Right for the horses mouth, the FAQ section on their website is wrong, and it is 62gr M855. Its also said from from a 20" barrel, but its actually an average between the 14.5" and 20" barrel.

Here are a couple reference websites which prompted my call.

http://www.ar15.com/forums/t_3_18/229420_.html

http://www.ar15.com/archive/topic.html?b=3&f=18&t=340944