AR-15 zero/sight in?

[Shrinkmd]

I have never adjusted the front post of my rifle, and the Bushmaster manual says it was "factory laser bore sighted". It finally dawned on me (big duh, as I have had to adjust my Mosin to not shoot high at 100 yds) that the thing was probably zeroed at 300 yds for the 62 gr current load.

Is this true? And if it is (it would explain why they're all high, again big duh on me for forgetting this simple thing and instead thinking I magically forget how to shoot every time I shoot this rifle) do people who shoot mostly at 100 yds just rezero the rifle, count the notches they rotate the front sight to get them all at POA at 100, or just shoot for groups? Or is it better to keep the 300 zero and just not worry about it (or try out the 200 or 300 yard line, which I've been meaning to do)

I shoot a lot of the ironsightaction.com 8/4MOA targets, and there is something satisfying about putting most of your shots in the white on a good day.

Thanks

 

[DMK]

The military zeros never made a lot of sense in the real world. The Springfield 1903 had a zero at 547 yards. You know how high that is at 100-200 yards? Something like 10" high at 100y.

Even with the flatter shooting 5.56 and a shorter 300 meter zero, the M16A2 zero still doesn't make much sense considering the trajectory of the ammo.

I use the IBZ for all my AR15s. You zero the rifle at 50 yards/200 meters using the front sight post to adjust. That puts you at about 1.9" high at 100 yards and +/- only 2" all the way out to 250 meters without any elevation adjustment (similar to a 200 yard zero in 30cal guns). If you have a carry handle, you calibrate the sight so the range markings still work, approximately.

More info on AR15 zero options here: Methods of zeroing at the Maryland AR15 Shooters site.

I never trust a factory to have the zero right with my ammo. Always set and verify the zero on a purchased gun.

 

[Shrinkmd]

Thanks. After some more searching off site I found that Maryland IBZ to try out. I think that will be my next range project, since we have 50 yd and 50 meter available at the smaller distance.

If I ever need to shoot at >300 I guess I can always rezero (but most likely would be using optics at those distances anyways)

Thanks