One of the most common issues I have seen with new Carbine students is their lack of knowledge about where their point of impact is at close ranges. I spoke with a student who could shoot his M4 out to 600yds with his ACOG, but did not know where his POI was at 50yds. Just about every 5.56 gun is going to be capable of hitting a man size target at 600yds, but the Carbine is really meant for close quarters combat. I’ve noticed a move away from magnification on many M4s because you really undermine your speed if you are relying on pin point accuracy from 100-600yds and don’t realize that you are completely missing a moving target that is 40yds away from you because you can’t track it.
One thing I do not recommend for an M4 is magnification over 4x. If you go hunting with your M4 and are fortunate enough to be able to do that in your State, then go ahead and put a 3-9×40 scope on it, but that will be a hinderance in a combat situation under 100yds. I still believe the best CQB combat optic is the Eotech, although I’d like to see a reticle that doesn’t fail when the batteries go dea. The Leupold CQT is a nice optic, but the FOV is not as good at the Eotech rifle scopes. I hear a lot of BS about people complaining about how the front posts on their rifles cover targets at close range, but I recommend that people keep a front post available. There have been so many times that I have forgotten to flip up my rear sight and just used the Eotech glass as tool for getting a sight picture and just used the front sight post for targetting. I did a test a few years ago where I saw virtually zero change in accuracy between just used my Eotech and front sight post and using a flip up rear sight.