Like this one?
https://www.rainierarms.com/?page=shop/detail&product_id=4347
Like said above, likely somewhere around 1.5 MOA.
Not sure if you want an alternative, but you could order a very similar BCM upper with the 14.5 ELW (or ELW fluted) barrel and I think the groups would be better. Not precision, but better, maybe 1 MOA give or take. There have been some very good reports on the ELW barrels on m4carbine.net. Going this route gets you a lighter and likely more accurate barrel and saves you some money, $1350 ($8-900 for the upper with either a BCM comp or BC1.5 pinned and about $435 with a BCM lower from G&R).