Even though it's been legal to buy gun silencers -- technically known as supressors -- in Minnesota since 2015, few people actually own them because they're so hard to get.
Suppressors are highly controlled, classified alongside explosives, poison gases, and machine guns by the National Firearms Act. Deep-pocketed buyers have to undergo a lengthy background check that could take more than a year, and pay a $200 transfer tax.
As a result, crimes typically aren't committed with suppressors. Hunters and range-shooters are also deprived of a tool to protect their hearing.
U.S. Rep. Jeff Duncan (R-S.C.) -- who told McClatchy he's hard of hearing in one ear because he never wore earmuffs when he shot as a kid -- wants to make it a lot easier to buy suppressors. He proposed the Hearing Protection Act, which would remove the $200 tax and require that purchasers pass only the National Instant Criminal Background Check, used for most ordinary firearm sales.
That measure passed committee on Wednesday, advancing to the House floor.
Democrats and gun control groups are predictably agitated by the NRA-backed bill, and the ensuing debate is unfolding like every other conversation this nation tries to have on gun policy, a screaming tug-of-war full of toxic passions.
In Minneapolis, where law enforcement relies heavily on ShotSpotter -- acoustic surveillance technology that senses exactly where guns are fired throughout the city -- the Hearing Protection Act could have unfortunate consequences.
Since 2007, ShotSpotter has alerted police officers to crime scenes even before emergency calls start coming in, prepping them along the way with data such as the type of gunfire and number of shots fired. Rapid response allows officers to better recover discharged shell casings for use in prosecution.
According to a statement from ShotSpotter CEO Ralph Clark, the technology has been able to detect suppressed gunfire in the past. However, it's not clear how consistently ShotSpotter is successful.
"Although we have not formally tested the theoretical impact to our system, we intend to do some targeted testing in the near future," Clark said. "We believe we will have various options, ranging from increasing our sensor array density to developing software/firmware, to address the dectection of suppressed gunfire if it were to become a widespread issue."
That is, if suppressors become easier to get, and people start using them to shoot each other, ShotSpotter may be ready to roll out better sensors.
Minneapolis Police spokesman Corey Schmidt had a more definitive response: "The ShotSpotter system is not able to detect a gun that is shot while using a suppressor."
Although the Hennepin County Attorney's Office doesn't have precise stats on how prosecution of gun crimes have improved with the use of ShotSpotter, it's so frequently mentioned in criminal complaints that it's clearly invaluable to law enforcement, says spokesman Chuck Laszewski.
Recalling Minnesota's debate over suppressors two years ago, he says there were surprisingly few facts as to the decibel threshold that can be detected by ShotSpotter, the decibel level of suppressed gunfire, and how that compares with the sound muffled by proper earguards.
"The gun people were saying contradictory things. On the one hand they would say the silencers aren't like the ones in Hollywood movies and still end up making an incredible amount of noise. But on the other hand we gotta have them because they'll protect our hearing," Laszewski says. "Well, it can't be both of those. And as far as I can tell, nobody called them on that contradiction."