boresighting an M4

[chu lai 68]

Is it possible to use one of those boresighting kits to boresight an Ar15 with scope mounted on carry handle? Wouldn't the scope be too high?

[XHairs]

It's not too high; just higher than the bore. Adjusting sights (or scopes) is a triangulation. The boresighter is limited in effective range and will just get you close, plus it's based on a unrealistic linear flight path. I use a ballistic trajectory calculator then print and laminate a small chart that I take to the range, based on a 300 yard zero.

http://www.eskimo.com/~jbm/ballistics/traj_basic/traj_basic.html