I believe that was the point of the "function test." Clear the chamber, pull the trigger, cycle action while trigger is still depressed. If the hammer falls again when cycled, it is full auto. If after cycling, the trigger is released and resets without the hammer falling, it is semi auto.
FWIW, that LEO knew his stuff. Well done on his part.
I think I was less than clear. I agree with you. "Reasonable suspicion" does not even mean "more likely than not" (50+% certainty). It is much less than that. The way it was explained in law school is that, even though the numbers are kind of arbitrary:
Reasonable suspicion is 35% or more probable that there is illegality.
Preponderance of the evidence is 50+%.
Beyond a reasonable doubt is, maybe 90+% sure.
The officer does not have to know with certainty that the weapon is illegal to make a stop and check. He just has to have a reasonable suspicion. He does not have to take the subject's word for it...that is decidedly unreasonable.
People may not like the law, but this was thoroughly, completely within the Terry v. Ohio standard. Don't like what the officer did? Change the law, 'cause what his did was well within it. Disagree and think he exceeded Terry? Please refer me to a case where the officer acted similarly and it was held improper.
As for those who say "...but full autos can be legal too..." The officer made it clear at least twice that if it was full auto, he would require additional I.D. as required by federal law. If it was full auto, arrest would not be the next step- checking to make sure he was in legal possession would be. Again, the officer followed the law. Don't like the law- change it.