So I've finally have some funds available to complete my MATEN build. Right now I have a Matched MATEN NIB upper and lower. I'm torn between at 6.5cm barrel and a .308. Main use will be plinking at the range. I am looking at a 20-22" barrel with a rifle length gas system. I am building a big brother to a MEGA AR that I built. Is the match ammo selection out there for the 6.5cm as it is for the .308. I'm not going to be reloading any time soon which is why I am leaning toward the .308. Ideas and opinions?