I am new to using rifle scopes, so I need lots of help.  I was in the Military and am a Police Officer in Nj and I have fired M-16's with Aimpoint.  I just purchased a Bushmaster Varminter Rifle and I am waiting for my Leupold MR/T 1.5X5 scope to come in.  

1.  I want to use this rifle from 10 yards to 400 yards.  Most companies tell you to zero your scope at 100 yards.  If I zero it at 100 yards, how will it shoot at 10-25 yards?  will it shoot high on the target?  I always thought it would be best to zero a Medium range scope at 25 yards so it could be used from close quarters to medium range (400 yards).  

2.  If I have my scope at 5 X magnification and I shoot at a target 300 yards out and the bullet hits center chest.  What happens if I set the magnification to 1.5 X magnification and aim for the same spot?  will it still hit the same spot?  Basically my question is if I change the magnification level will that also change the point of aim.  

I appreciate any help to my questions.  

Zero at 100 yards and then fire your rifle at various ranges to determine your Poi at each distance.  That is gonna be the best way to learn.

Your scope should not change POI when you increase/decrease magnification.  Older inexpensive scopes were bad about this but is not seen today in good optics.  

Hope this helped and good luck.

Thank you for your reply.  I figured I'd either zero it at 100 yards if I am going to be doing longer range shooting, or at 25 for medium range.

Here's an excellent page for "trying out" different zero ranges to get an idea of where you can expect impact at various distances. www.eskimo.com/~jbm/ballistics/traj_basic/traj_basic.html