A nice 3x magnifier will really help hits at 100, especially getting them where you want them. I have both the original Vortex 3x and the Aimpoint 3X C version and they work well. I like the factory Aimpoint mount better, as it flips easily and removes faster, but the eye relief on the Vortex seems a tad better - in the same position on carbines I have to slide my head forward to get a full view or move the Aimpoint 3x back a slot on the rifle.