I was out at the range today, and had trouble getting my M4 zeroed today. BTW, I was trying to zero at 50 yards since I've heard that it's a better battlesight zero than a 100 yard zero.

First of all, is it best to zero with the big or small hole apiture. Depending on which one I had it set on, my point of impact would change. It seemed that the small hole sight shot lower than the large hole sight. Is there a reason for this? A friend of mine told me that it's best to zero with the small hole. True?

Also, if zeroed at 50 yards, what should the point of impact be at, say 100 yards? It seemed my shots were higher than they should have been when I swithched from the 50 to 100 yard ranges.

Also, I was zeroing with out moving the knob on the side. I kept it set at the 3/8. And, my knob bottoms out at one click past the 3/8 mark. Was that my problem?

Any help or suggestions? I'd like to have a zero that would be good for combat conditions, as well as plinking at 0-100 yards.

First off, you do know that all elevation adjustments are done with the front sight post.  You can use a Santose-style method if you like, but if you're only going to be doing 100-200 yard plinking, you won't need it.  A zero at 50 yards is perfect for you - you'll be about 1/2" high at 100, and 2" low at 200.

For the M4, adjusting elevation is also very easy at 50 yards:  each click of the front sight post is around 2MOA, or [b]1" at 50y.[/b]  Take any standard target, particularly one with grid measurements, and zero from the bench (and sandbags if available) at 50.  Fire a 5-rd group, and measure/adjust the front sight post, remembering that each click is 1"...then fire another 5 shots.  This is a quick, dirty, but effective way of zeroing that M4 for <200 yards.  

If you want to zero for 300, shoot at 50 yards, but get the shots where they are [b]2" high[/b] above the bull, and you will be nearly dead on at 300.  Hope this could help.

[img]www.auburn.edu/~littlcb/new jew.jpg[/img]

Jewbroni, that's kind of what I figured, but still wonder about the difference I was getting with the small hole and large hole sights. Which one should I use for sighting in?

Also, should I leave the 3/8 setting where it is and do this, or should I bottom it out and then set it back to 3/8? Or is this only useful for the 300 yrd zero?

BZO aints used fer no bullseye shootin'.

BTT^^

Seamusmcoi,

A 'wise man' once told me not to worry about where around the 8/3 marker you are, as long as you know your zeroes and your respective come-ups.  If it matters to you, then all the more reason to get a 300M/Y zero (so the 8/3 will actually be an accurate reading).  

Having the rear sight base bottomed out BELOW 8/3 is actually PERFECT for 300 yard zero, as you can notch it down a click or two and have it zeroed at 100 (bottomed out)or 200.  Effectively, 8/3 -2, that is two clicks below 8/3 [zeroed at 300M], will zero you in for 200 yards, and 8/3 -3, three clicks below 8/3, will be zero at 100 yards.  In other words, get it to where the 8/3 is 3 clicks up and zeroed in at 300, and you will have a COMPLETE set of zeroes and come-ups for 100+ yards, out to the effective range of the rifle.

As far as the aperture goes, ONLY ONLY ONLY use the small aperture.  The large one is useless, and is reserved for battle or other CQB situations.  Using the 50 yard method I provided, you will get substantially good zeroes at 300 yards.  Email me if you need specific help with adjusting the rear sight turret to whatever position you wish on the range marker.

[img]www.auburn.edu/~littlcb/new jew.jpg[/img]