The OR Supreme Court concurs that "assault weapon" and "high-capacity magazines" are arbitrary terms. 

Via Oregon Live: 

The Oregon Supreme Court ordered changes Wednesday morning to the ballot title for an initiative that would ban the sale of many semiautomatic guns and high-capacity ammunition magazines in the state...

In an opinion issued Wednesday morning, the court said Attorney General Ellen Rosenblum must make changes throughout the summary of the initiative that voters would see if the proposal makes it onto the November ballot. 

Several gun rights and hunting groups appealed to the Supreme Court to modify the ballot title, saying the use of such terms as "assault weapons" and "large capacity magazines" is misleading.

The ballot title that was appealed to the Supreme Court reads: reads: "Prohibits 'Assault Weapons' (Defined), 'Large Capacity Magazines' (Defined), Unless Registered With State Police. Criminal Penalties."

The state Supreme Court agreed with the gun rights and hunting groups that "assault weapons" is an imprecise term that voters could interpret many different ways, and the attorney general's reference to the definition within the full text of Initiative Petition 43 was not adequate to explain the impact.

Chief Justice Thomas Balmer wrote: "We conclude that the (ballot title) caption could accurately state that the proposed measure would criminalize the possession and transfer of many semiautomatic weapons, as well as magazines holding over 10 rounds."

Read more here.