how accurate is the bcm mk12 upper?

specops47

Private
Minuteman
May 30, 2012
7
0
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With a leupold mark 4 4.5-14.5 mildot and larue scope mount. And what is the most accurate ammo for this upper factory? Thanks so much I plan to it on a spikes tactical lower with the battle group trigger set and magpul moe stock. Thanks