bullett trajectory

[newguy]

I sighted in a ar rifle at 100yds 3x9 scope .grouping about 1 to1/2 Depending on me. The question I have is that is it normal to be shooting 1 to 1/14 low at 40yds

I also sighted m4 16in barrel w/comp m3-2moa w/3power mag. at 50yds .and its dead on at 100yds.

Co
could you please help me with this. Or is just normal. with both scopes and rifels

thanks for your time and advice

[Failure2Stop]

Closed, duplicate thread.