Video forensics and ballistics gel prove 100% the shot was high-velocity.
I can make ballistic gel perform however I want by changing bullet configuration, weight and powder charge and still maintain "high velocity" with any single center fire rifle cartridge. Until they match the powder residue left on both the rifle bore and the bullet, they won't be positive the caliber (unless they have the actual bullet).
And, ballistic gel doesn't have the characteristic of a bullet hitting something hard (bone, spine, etc.)