My personal preference is the 6mm ARCin a mini Bolt action. Though for your intended use distance, & if factory ammo is a factor the 6.5 Grendel may edge out the 6mm arc. Pricing & availability of a variety of loads in 6mm ARC is simply, pushing the 6.5 Grendel to the better supported side.
As a bolt action die hard reloader guy, the 6mm ARC may arguably be better supported.
love, joy, peace, patience, kindness, goodness, faithfulness, 23 gentleness, self-control
& Proverbs 21:19
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