The case you linked is the Supreme Court case regarding this situation, and they reversed the lower court and appellate court's decision. They said that regardless of ammunition, the investigators had PC to inspect the modified AR, and that the search and subsequent seizure of the rifle were legal. The Supreme Court does not reach the same conclusion you did, about "no mag, no machine gun." In fact, it says pretty clearly:[quote]
Carter was charged with one count of possessing a machine gun in
violation of RCW 9.41.190(1) and .010(7). Carter moved to suppress the
rifle, contending that the search and seizure of the rifle were unlawfully
conducted without a warrant. The trial court agreed and dismissed the
charges against Carter with prejudice. The Court of Appeals affirmed in an
unpublished opinion, and the State appeals. State v. Carter, noted at 112
Wn. App. 1046 (2002). We reverse.
The search of Carter's rifle did not implicate article I, section 7 of
the state constitution or the Fourth Amendment to the federal constitution
because there was no recognizable privacy interest in the AR-15. Carter
presented the firearm in open view of the students and invited them to
handle it. This precluded any expectation of privacy in the gun.
Additionally, the warrantless seizure of the firearm qualifies for the
exigent circumstances exception warrant requirement. We therefore reverse
the Court of Appeals and remand the case to the trial court for further
proceedings consistent with this opinion.