I suspect that has more to do with your desire to outlaw hunting in
all forms than preventing mass shootings since millions of "kids" are
given guns every year and a minuscule fraction ever do anything wrong
with them. (other than murder helpless animals)
No problem in states that allow "kids" to have rifles for hunting as
long as they are of the legal age for that state and the rifle is
registered to them. Of course the parents still have parental
responsibilities as to how and when it is used and stored.
Are there states that require the registration of rifles? Massachusetts doesn't, but I see
California does.
"The California Department of Justice ("DOJ") retains information about the purchaser and seller of
all in-state firearm sales and transfers, and requires that any firearms imported into the state be
reported to the DOJ.[14] Furthermore, the Attorney General is required by law to maintain a registry
containing the fingerprints and identifying information of the transferee, and the unique
identifying information of every firearm transferred in the state, pursuant to §11106.[15]"