Ok guys, here's the deal. I live in a very large city and the longest range I can shoot at is 55 feet. I have a new upper receiver I got with a gun I bought and I want to zero it according to the guide on this site. I've set the mechanical zeros on the rifle, so now I have to figure out how to zero for 25 meters at 15.24 meters (50 feet). Logic would dictate that I could somehow calculate how low a site zeroed at 25 meters should hit at a shorter distance and then aim for one point and expect an impact at a lower point to achieve a proper zero. I realize the math involved isn't very complicated, but I'm not familiar enough with the balistics involved.

Any help would be appreciated, however "find another range" is unfortunately not an option for me.

From Forest; Zeroing Methods

Have any of you tried the Improved Battlesight Zero described in the link above?  It sounds like something I want to try.

I use the improved 50 yrd zero...  Works great for me as 99% of my shots never go over 200yds