It very much depends on what you mean by "it is OK." OK from which perspective?
I've fired a full-size Uzi (my personal weapon during my Dutch military service) on automatic, and it's quite controllable. That does have a thing or two to do with the fact that it's more than twice as heavy (3.7 kg vs. 1.5 kg), and has less than half the rate of fire (600 rpm cyclic vs. 1,250 rpm cyclic), as a Micro-Uzi.
With a competent,
experienced instructor taking a hands-on role (as opposed to some 15 year-old), and with a weapon that's easier to keep under control than a
Micro-Uzi, there's no reason letting even a 66-pound eight year-old fire an automatic weapon shouldn't be perfectly safe. Note:
an automatic weapon, not (I reiterate)
this particular automatic weapon.
Now, let me state, as a parent and a former soldier (technically inactive reserve, but I'll seriously surprised if they ever try to call me up again), that I'm not particularly supportive of the idea that firing an automatic weapon is appropriate entertainment for an 8 year-old. But that's from a pedagogic aspect; purely from a physical safety aspect, this can be done perfectly safely.
Then there is apparently the legal aspect, namely that (according to the ABC piece linked to by RamboLiberal) it's illegal to "furnish a machine gun to a minor" in Massachusetts under Massachusetts General Law Section 130 (
http://www.malegislature.gov/Laws/GeneralLaws/PartI/TitleXX/Chapter140/Section130), but the law does not define what "furnish" means. The section also seems to apply primarily to licensed dealers in firearms, and contains a bunch of exceptions for parents "furnishing" their children with firearms and instructors "furnishing" students with firearms, which would lead me to think that "furnish," in this context, means "to grant control over while the recipient is not under
immediate supervision." (To compare, here in Washington state, my state of residence, state law makes the distinction between "having in one's possession" and "having in one's control" a firearm; the distinction being the absence or presence, respectively, of a supervising individual eligible to own a firearm. For example, if my 16 year-old niece from California or a friend from Europe comes to visit, I can't lend them one or more of my guns and let them take the guns to the range without me present; I
can take them, and my guns, to the range and let them handle and fire the guns under my supervision. Or I could lend the guns to one of my niece's parents, and let them take her to the range and supervise her while she shoots.) But the legal aspect, like the pedagogic aspect, does not reflect on the physical safety aspect.