Pleasure to be a part of your group. I grew up hunting in Colorado, and am now coming back to my firearm roots - after years of bow hunting for big game. My goal is to find the specific model of AR before I purchase the rifle. I plan on a lifetime buy that has been on my "wishlist" for years. I am looking for an M4A3 -- home/target/coyote, not really extreme distance. I already have a handful of rifles (bows and pistols) from a Rem BDL 700 to a Mosin Nagant to Sig.
I am trying to decide between a Colt 6720/1 Flat-top, a Rock River arms R4 Entry Tactical detachable, OR ~ I have found a Smith and Wesson M&P Sport for under 600$. The M&P It has no forward assist nor dust cover -- So should I buy the "complete" AR or save over 300$ to use towards the other rifles I want ? Or wait even longer and get a Knights Armament, high end ? I am not sure what to do as I want to pick the best choice eventually carried on by my son, while I am not in the field of battle. Any suggestions, brands, discoveries, all ideas are welcome -- I want to learn...

These are the questions I am looking for, what do you think? Colt, RRA Entry Tactical, Smith and Wesson M&P, high end, or ?

Thanks and good shooting to you all,

Ozzie