Mebe007 Wrote:So I have an aero m4e1 lower and sn aero upper sitting around. I just finished a 16" grendel, my first. I have another ar15 in 5.56 already. I'm debating building this into either a 20" grendel or a 20" 6mm arc. Would love to hear opinions ions. Not sure if it's worth diving into reloading for yet another caliber to reload
What is it you are wanting the rifle to do, or not do. Arc will offer lighter & Higher BC bullet offerings, in turn less recoil, more velocity & flatter shooting all else being equal & all will not be equal between two cartridges. 6.5 Grendel will offer More momentum & energy on target.
My personal experience will differ from your use in that I have used both cartridges in only bolt action rifles with 22" barrels. In this case my preference has been heavy for the 6mm ARC for many reasons. My use is target shooting geared towards deer hunting inside of 300 yards. ARC offers all I need on target with less recoil, A flatter bullet path & a wider bullet selection compatible for the cartridge, as a reloader.