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.