Why not keep things simple, I think others have missed a little on their dimensional analysis here so I'll give my .02. I come up with 2.9cM per 100M: 1.0472"/100yds X 1yd/0.9144M X 1cM/.3937" = 2.9cM/100M
20MOA X 2.9cM = 58cM or 22.8" which is pretty darn close to your stated 25" at 100Meters. Which is probably well within the margin of error.
Last edited by devildoc; 03-27-2008 at 12:18 AM.