He's 13 now, but stocky and use to some of my bigger rifles. So 9 rounds through the mosin weren't too rough on him---he was pretty spent after that though. 180gr. hunting loads for it get your attention pretty fast over the usual 147gr. plinking loads.
As to the 6mm question---those are my long-range target loads, not hunting loads---it's all I had loaded at the time and brought it just for kicks. I'd have to head out to the shop to get specific load data for you, but they're 90gr. Sierra FMJ/BT. Haven't chrono'd em since moving back to the mountains from the desert, but they're somewhere in the neighborhood of 3200 fps. Measured from center of bull, those hits are just under 5.5" high at 100yds---so, your 7" estimation isn.t far off. And, it probably works out closer to a 425-450 zero here since that load was worked up in a 115-degree 0-humidiy desert.