Zeroing my reflex on a 18" 308 ar10

[20ozjolt]

Attempted searching didn't find results.

I have a reflex hollow sight on a cantilever mount on my A.R. 308 I did a rough zero at 50 yards for now but I'm wondering what the ballistics crossover points for the 308 are.

Is it the same or similar to 223 where if I zero at 50 it'll be dead on again at 200 or the distance drastically different with the 308.

[T-Dot]

Is it the same or similar to 223 where if I zero at 50 it'll be dead on again at 200 or the distance drastically different with the 308.

20ozjolt, I hope this is what you're looking for: it's from Winchester's trajectory calculator app: the red is 62 grain 223, and the blue is 147 grain 308, both FMJ. In short, the trajectories are pretty similar but you're going to see 308 a little short of 5.56. This is with standard FMJ, again. I'm sure you could see something different with match ammo and all that.

Here's a picture to give you an idea (the bottom picture is a zero at 50, and the 308 comes in about 25 yards shorter at 300m).

34245

[20ozjolt]

Awesome thank you

[Failure2Stop]

For a GP 7.62, with muzzle velocity under 2600, a 150 meter zero works well to balance close range and midrange stuff, since reduced distance zeroing schemes are weak sauce.

From Tapatalk:
Jack Leuba
Knight's Armament Company: Military/Govt Product Liaison
F2S Consulting: Director of Shooting Stuff

[T-Dot]

For a GP 7.62, with muzzle velocity under 2600, a 150 meter zero works well to balance close range and midrange stuff, since reduced distance zeroing schemes are weak sauce.

Sorry, I'm not sure what you mean by "reduced distance." Can you explain?

Thanks.

[MistWolf]

In other words, use a short range zero to get you on paper, then finish zeroing at the longer range. In this case, finish sighting in your 308 at 150 meters as F2S recommends. It will give you a good, flexible trajectory.

If you only sight in at reduced ranges, you can only guess where your zero is going to be at further ranges

[T-Dot]

Ah gotcha. I guess I assumed that when someone says "50 meter zero" they really mean 50\250 or whatever the reciprocal is, with a confirmation of zero on the far end, as a given.

[nimdabew]

Sorry, I'm not sure what you mean by "reduced distance." Can you explain?

Thanks.

Zeroing at 33m and assuming you have a 300m zero.