I am getting ready to order a Stag arms 3g that will primarily be used for hunting 400yrds and in, and some competition shooting (Close in and out to 600-800 yrds). I am not looking to reload 5.56 and have had good luck with Southwest ammunition. I am going to order a case of ammo but I have some questions. I need to know whether to get the 69 or 77 grain SMK's. I am assuming both of these rounds fit in the mag and cycle well. So what are the pro's and con's to both rounds? Is there a clear advantage to either one? Thanks.