Proponents of gun control in Hawaii argue that such laws work pretty well. In fairness to them, Hawaii has a pretty low crime rate, though I'd argue that's likely due to multiple other factors that have nothing to do with firearms, but we all know that those proponents would disagree.

Among the laws in the Aloha State are restrictions on any adult under the age of 21 owning a firearm.

And they've got gun registration, which should keep these people from having a gun no matter what.

Yet it seems they also don't want them to be able to buy ammunition, either.

The 51-member Hawaii State House on April Fool's Day approved SB2845 with only five Representatives voting against the measure. The bill had previously passed the 25-member State Senate by a 22-3 vote. For the record, the entire state legislature only contains eight Republicans. 

The proposal, which now goes to conference to work out differences between the versions pass by the respective chambers, not only bumps the age of purchase for ammunition to 21 and requires retailers to check the government-issued ID of purchasers to verify age, but also makes it a crime for adults under 21 to "own, possess, or control" ammunition. This means retailers and distributors could be criminally charged should they make a sale to those under 21. 
 
The bill has a vague exception for those under 21 that are "actively engaged in hunting or target shooting or going to or from the place of hunting or target shooting," but leaves out any mention of possessing ammunition for defensive use or just what qualifies as "actively engaged." 

... 
 
"Section 3 creates a new felony offense for anyone under twenty-one years old in possession or control of a firearm," noted the office headed by State Public Defender Jon Ikenaga. "This means that young people are categorically banned from carrying firearms for self-defense purposes. This ban runs afoul with the Supreme Court’s decisions about the Second Amendment making it ripe for a challenge by the defense bar if prosecutors intend on using the statute and gun activists in the civil arena."

The exceptions to this really make this bill seem like nothing more than a pain in the butt than an actual restriction. Anyone can just claim they need the ammo to target practice or to hunt, thus bypassing the restriction.

And since no one uses all of their ammo while hunting and many don't use it all at the gun range, these folks are bound to have some left over.

Besides, if their gun control works so well, why do they need ammo control?

Yet the effectiveness of the law really isn't an issue. The problem is that this is yet another example of pretending that the right to keep and bear arms isn't really a right, but a privilege that can be restricted so that legal adults can't exercise it.

Imagine, if you will, the outrage among proponents of this measure if we instead suggested raising the voting age to 21. They'd go nuts, yet they think nothing of restricting the right to keep and bear arms.

My hope is that the law goes no further than it already has, but Hawaii loves gun control. It likely will, in which case I hope the measure is smacked down hard by the courts. Just don't let it go before the state supreme court, otherwise the "spirit of Aloha" might lead them to further idiocy.