I have 3-9x40 Bushnell on both of my S&W MP15 Sports and I can't see the front post.
I use simple Millet one-piece mounts that give me clearance for the charging handle and rear MBUS flip up for quick changeover.
I'm not a good shooter, but the combo serves me and my old eyeballs well. (I ended up with identical combos - one lives in my truck)
Most certainly not a precision rifle, and I'm not a marksman, but this is a very typical and repeatable 10 shot group at 125-130 yds with 62gr. At just a bit over $700. including the scope and a pair of 30 round magazines, it's a good utility rifle.