Wednesday, January 18, 2017

The Hearing Protection Act

I think that of the stupid and illogical restrictions passed in the National Firearms Act of 1934, the most illogical is the restrictions on silencers, which obviously aren't even firearms.  It's a silly requirement that imposes a $200 tax that was crippling when it was enacted, but has dropped in impact as our currency is inflated away.  In 1934, $200 was many times the cost of a gun; today, $200 is close to the price of the lowest cost guns but a fraction of the cost of higher end handguns.  Today, the application process and delays seem to be the most significant hindrance to widespread use of silencers.  Hopefully, the Hearing Protection Act can remove those false hardships. 

Hat tip to No Layers - Only Guns and Money for the heads' up warning he posted about the campaign against the Act starting in earnest.  He reports receiving the following email:
Mark Kelly, of course, is Gabby Giffords' husband, "affectionately" known as Space Cowboy.

The problems with this, of course, only start with the fact that while it's technically correct to say "silencers do suppress sound and light", that's what they're designed to do, the rest of the email is just the usual fear mongering.  They don't back up the claim that silencers are attractive to criminals, and they don't describe the actual changes silencers cause, which while helpful are actually pretty minimal.  They're appealing to the ignorant whose only knowledge of silencers is from far too many movies that show a silencer reducing the roughly 160 dBa sound of a .45 handgun down to a soft, puffing "pfft" sound.  In reality, instead of the 80 dB noise reduction that movie sound implies the actual reduction is around 30 dB or what your typical hearing protection provides, which reduces the sound of a .45 cal handgun down to a loud blast on a trumpet or a loud passage in a stadium rock concert. Yeah, it's quieter but it's still pretty darned loud.

Put it this way: it reduces the sound out of a .45 handgun to the sound of a .22 rifle.  I think everyone still wears ear protection around .22 rifles today. 

John Richardson writing at No Lawyers puts it this way:
Having reported on hundreds of defensive gun uses on the Polite Society Podcast I have yet to come across mention of a criminal having a suppressor in his or her possession while committing an assault, robbery, home invasion, or murder. Indeed, more often than not, these miscreants use the loud sound of a firearm discharge to attempt to cow their victims.
The references to the ebil debil "gun lobby" and "corporations who manufacture and sell firearm silencers" tell you what they're really all about: just restricting the rights of gun owners for no valid reason, and thinking we're all just brain dead zombies who do whatever the "gun lobby" or double un-good NRA tell us to do. 

Disclaimer and technical tangent: after a career in RF engineering, decibels are second nature to me, and while guys are fussing and "dB chasing" in silencers, making a huge deal over differences of a single digit in noise reduction, like from 31 to 32 dB, and companies are selling different models by stating attenuation to tenths of a dB, It Doesn't Matter.  Audio has a lot of counterintuitive stuff to it, and one of them is that while the dB scales that audio guys use correlates with Sound Pressure Level and other lab-type measurements, how loud a sound is perceived to be follows different rules.  You're entering the field of pyschoacoustics, and it's filled with all sorts of unexpected things.  For one, the perceived loudness of a sound depends on its frequency.  Another, while the difference in measured sound pressure doubles for a 3 dB increase in sound level, if you give someone a volume control and tell them to increase the power until the sound is twice as loud, they don't increase it 3 dB, they increase it closer to 10 dB.  In other words, if you're shopping for a silencer and they tell you one is good for 131.3 dB and another is good for 130.8 dB, no one will ever tell them apart in use. 


  1. I've wasted HOURS trying to explain dB to people.

    Our weather forecaster at Sea Launch is a very intelligent guy, but I went around and around and around with him trying to explain that difference in power output between the two TWTA's we'd rotate on a schedule was only 1.3dB, but he kept saying "But it's 300 WATTS!!!". While 300 Watts of RF at 6GHz is generally nothing to sneeze at, it's completely irrelevant when that "300 WATTS!!!!" amounts to a 1.3dB difference between the two amplifiers.

    1. This is in the "don't get me started" file. I can't tell you how many times I had to do the "a dB is a dB" talk, or the "10 log vs 20 log" talk.

      I worked with a digital guy who used a phrase I'd never heard, but made me laugh out, "I've got the dB jeebies", when he'd ask for help. He usually understood it much better than the rest of his group.

    2. I'm old enough to remember when the USAF had to change T.O.s and training curricula from TWATs to TWT amplifiers because of the increasing number of women coming into the service. Then there was the mnemonic poem for remembering resistor color codes. Dad had it easier back it in the 50's and 60's in some ways. If you follow Cdr. Salamander's Diversity Thursdays, it makes me glad I'm long, long out.
      I remember dBs especially in regard to SAC radio systems that only allowed about 1/4 to 1/5 the distortion that a human ear could even perceive. Because everything must be better than perfect. Even the bolts holding the radios and computers in the racks down in the Minuteman launch control centers had to be tightened with a torque wrench to something like 30+-1 lb. Utterly ridiculous, but anything worth doing is worth overdoing, they said. Obviously things have slipped since that period of time, but morale was poor even then. SAC was a sink for my MOS.

  2. If suppressors will be treated as firearms under the Hearing Protection Act, will 80% suppressor kits come onto the market?
    And the machining of a suppressors seems far simpler than transforming a block of aluminum into an AR-15.

    1. You're absolutely right. They look to be a fairly simple lathe project, as long as you consider things like the high temperatures, disassembly for cleaning, and so on.

      I don't think there's such a thing as the 80% silencer. One of those things that "I read on the Internet so it must be true" about silencers is that the BATFE has zero tolerance on them. Should they be investigating someone, if they had a lathe and parts that looked like silencer parts, BATFE would go after them. Now there's a lot (a lot) of metal lathes in this country that could make a silencer so they'd have to be investigating someone anyway to find it.

    2. I was surprised by the crudity and simplicity of the Sterling sub machine gun silencers used by the British army. Essentially it was a tube filled with wire wool which was kept in place by a wire mesh arrangement which also formed the passage for the bullet.

      Now they WERE a silencer and with subsonic 9mm, all you could hear from a few yards away was the clack of the bolt going back and forward.

      They burned out pretty quickly though and needed repacking after about 500 rounds.

      Civilian types tend to have washer like baffles down the tube and are more robust though not as quiet.

      Phil B

    3. I think there's a lot of ways to build one, even without something like a 7x12 metal cutting lathe.

      Someone had a link to some stuff sold on Amazon that can be used as (or really are) those baffles, but they call them something else. Not to mention those "oil filter adapters" (something like this).