I went to the range today to sight in my new Bushmaster M4.  I read though the method described in the manual, and several other methods online.  A guy at the range helped me sight in, and I was getting sub 1" groups at 25 yards.  However, I'm still not sure if I did it right.

The elevation wheel bottoms out so the "Z" to the right of "6/3" is aligned with the line on the receiver.  I was under the impression that the "6/3" should match up to the line.   I'm guessing that I need to flip up the small sight and remove the allen screw to adjust the elevation wheel height so that it will bottom out on 6/3.

The manual describes adjusting to the 300m mark plus one click up when sighting in on a 25m range.  I know that I didn't do this, and suspect that my adjustment may be off.

Can someone please explain how to carry out the 25m zeroing procuedure described in the Bushmaster manual on page 34?  This is my first AR15, and the process is totally foreign to me.  Thanks.

Someone less tired and much more knowledgable than I, will soon help you. Until then,

check this out The Maryland AR15 Shooters Site. Many here like the Improved Battlesight Zero.

Good luck

What you did, or did not do, is for you to clearly explain.
I imagine you can re-zero your rifle during your next visit to the rifle range.
Pick one zeroing method.  Please don't mix methods.

The real truth is at 300 meters.  If you have access to a range with a 300 yard or 300 meter line, you could use it to verify your rifle is zeroed properly.  Some fine tuning may be required.

Record the direction and speed of the wind.  The effects of the wind may not show up at close range, but will have more opportunity to affect a bullet enroute to distant targets.  Again, fine tuning may be required and will vary according to the direction and speed of the wind.

Shooting a 1 inch diameter group at 25 yards should be good enough to keep you on the paper of the targets.  A battle-sight zero is supposed to allow you to engage targets of a certain size from 0 - 300 meters without having to adjust the elevation wheel of the rear sight assembly.  You might hit slightly above or below the center of the circle but, in theory, you'll still hit the circle.

Congratulations on the purchase of your new rifle.  I wish you success in learning to master it.

~Craig