25 yard zero with Aimpoint on a 2” mount.

[Hammer_Man]

I’m curious to know what is the consensus on zeroing a red dot sight mounted on a 2” mount at 25 yards. Do I want my POI approximately 2” below POA at 25 yards? For those of you running an Aimpoint on a 1.93” - 2.26” mount, what POI at 25 yards works best for you?

[markm]

I don't use that method, but you'd want the poi slightly less than 2" below poa.... maybe 1-3/4" to 1-1/2" low.... I.E. the bullet should be coming up some at 25 yards.

[opngrnd]

If this question is still unanswered next Tuesday, I'll shoot a group at 25 yards and share my results.

[grizzman]

What's the sight height above the bore? What is the bullet, and how fast is it travelling at the muzzle?

You're attempting to achieve a 350 yard far zero?

[TBAR_94]

I'm far from an expert, but I don't really worry too much about optic height when I zero. Pick a 25/300 or 50/200 based on the distances you shoot at, and then learn the hold offs at other distances. I use a 25m zero on most guns, but I zero at 100m on my 10.3 because I don't really shoot it further than that, so I don't have to worry about holding under.

[markm]

I guess I'm assuming the OP plans to zero at 25 for a poi/poa match at 100 yards. But I could be wrong.

[Hammer_Man]

To clarify, I plan to run an Aimpoint on a 2” mount on my general purpose M-forgery carbine. Either a Comp M4S on a Unity FAST mount (2.26” optical centerline above bore), or a Comp M5 on a KAC high rise (2.33” optical centerline above bore). In theory I’d like to replicate the 25m/300m zero I learned/used in the military. I heard that the taller bore offset can affect your holds at distance, so I was curious if that would affect POI when zeroing at 25 yards.

[Hammer_Man]

Double post.

[grizzman]

The tall rear sight is definitely going to change the far zero compared to a standard ~1.5” mount.

Do you have a chronograph? There are multiple different apps, websites, and software that can be used to determine external ballistics , but they all require the bullet (for its BC) and the muzzle velocity. The sight height above bore data point can be adjusted in the software.

FYI, the Unity Fast mount isn’t going to put the optic center at 2.26” above the bore. It’s likely putting it at between 3.25" and 3.65" above the bore.

[opngrnd]

My rifle wears a Steiner 1-4 in a 1.93 mount. Zeroed at 200 yards, I shot a group 1.5 low at 27 yards. Looking at Strelok, I'd zero at .5" low at 25m to get an approximate zero at 300m.

[Hammer_Man]

My rifle wears a Steiner 1-4 in a 1.93 mount. Zeroed at 200 yards, I shot a group 1.5 low at 27 yards. Looking at Strelok, I'd zero at .5" low at 25m to get an approximate zero at 300m.

Awesome, thanks for the info!

[Pappabear]

As we always say, the bullet don’t lie. So set your zero and learn your hold overs or unders. Try different ammmo and then finally your goto ammo depending on your gun. Looks like you are well on your way.

Funny story, I have a friend that inherited a 308 from his FIL. He worked for Coors and the owners were big hunters so he went on all these amazing Elk and deer hunts. He told me for years about his hunts with pictures….I go back to KY and ask to see his rifle. I asked, did you zero at 100 yards or 2 inches high at 100? He looked at me confused and said what are you talking about, I explained again. He replied “ I have never zeroed my gun, I figured my FIL put the scope on so I’m good”. And he killed everything. I laughed at myself and thought good point- I guess.

That being said I’m still anal about dialing my scopes in, but how likely are we going to miss a bad guy inside 100 yards regardless if we set 25-50-100 yards? Not likely but I still do it. Just a story to put it all in perspective.

PB

[Coal Dragger]

^ This.

I zero most rifles and carbines at 200 yards, and then verify other distances. Realistically on anything inside 200 yards to 50 yards with a 5.56 zeroed at 200 yards, I will put the dot, crosshairs etc on the target and press the trigger. With a 2 MOA red dot or center dot in an LPVO the aiming point at 100 yards is large enough to pretty well obscure any difference in POA vs POI.

Inside of that I have to hold high to account for height over bore. Again on most targets outside of dot torture, a tight head box, or an occluded target you can still essentially ignore it and just drive the gun.