Trijicon M4 Optics what bullet weight?
You do have to be careful who you listen to when you shop around for optics for your M4 carbine. In recent years it is not that uncommon for people to be using 75gr or 77gr ammuntion in their M4 Carbines, and if you change the bullet weight of your round, you can void the purpose and uses of your bullet compensator. I know several people that think there is no difference between the M855 and the M193 round when you sighting in with a Trijicon ACOG, but this is not the case. If you are using something like the Trijicon TA01NSN optics and you want to engage a target at 400yds, there is going to be a big difference in where you hit. If you pay attention the ballistics of the ammunition you are using and you use the good stuff, you should be dead on with your Trijicon sighting system.
I use an LWRC M6A1 with a Trijicon TA01NS which is my favorite optics, primarily because I can never really adjust to anything but crosshairs on my reticle. I have used the TA31F-G on occassion but the Trijicon TA01NSN is still my favorite optic. The iron sights are an added feature which do sit high, but an easy transition from medium range to close quarters combat shooting if need be. You also have a night sight on the front sight. You can always swap out the iron sights for one of the RMR sights if you want to.