From Reason.com:

By contrast, proposals to raise the minimum purchase age for long guns at least have something to do with the Buffalo and Uvalde attacks, since both shooters were 18 years old. But it is hard to see how that policy can be reconciled with the Second Amendment unless you assume that 18-to-20-year-olds, unlike older adults, do not have a constitutional right to keep and bear arms. Two federal appeals courts recently rejected that proposition, citing a long tradition of gun ownership by young adults.