Summitsittin
Actually both my grandsons have AZ cow youth tags.
As I commented on earlier the 12 yr old will use his new Tikka with probably the 120 TTXS.
His younger brother, 10 years old, will use his mothers 7-08 with the 120 TTXS . It's a right hand Rem 700 youth model.

Everyone has their own preferences on bullet choice for elk. I watched my daughter place a 120 TTXS from her 7-08 thru both shoulder of a big 5X5 at over 200 yds.
The bullet exited and the bull dropped right there. I'm sure they will work in the 6.5 CM
I'm sold on Barnes and that's all we use in our 300 WSM, 300 Win, and 338.