And a one year update on the temperature range that started this thread. Check out the outdoor temperature records. The outdoor sensor is on the north side of the house under the eaves.
I would not pay any of these prices, but it is the first time I have seen ammo on the search in several months.
https://ammoseek.com/ammo/6.5mm-grendel
I bought 10 boxes of Monarch (Academy's brand) 12 gauge #8 shot, 1350 ft/s for $6.99 each. A recent purchase recommends 1300 ft/s or higher ammo for the break-in period.