Suppressors (aka silencers) have NEVER been illegal at the federal level. That is a state issue. Currently they are legal in the following states: AL, AR, AK, AZ, CO, CT, FL, GA, ID, IN, KS, KY, LA, ME, MD, MI, MO, MS, MT, ND, NE, NV, NH, NM, NC, OH, OK, OR, PA, SC, SD, TN, TX, UT, VA, WA, WI, WV and WY.
They may be legal in CA and IA with a valid FFL (but don’t count on it)
Facts about Suppressors (AKA Silencers)
Tax stamp. $200
Threaded barrel $120-400
Suppressor $500-1500 avg of units surveyed $850
Sights (if you want to be able to aim) $50-250
Adds 5-12 inches to length - there are a few shorter and longer.
Add 11-16 oz to weight
Note that I haven't looked into wet suppressors as I have no personal interest in them - I may add that data later.
Keep in mind a typical polymer pistol weights in at 25oz unloaded, you will be adding significant weight at the far end of the barrel.
Reduces noise by about 32bBA on average. 22-35db depending on mfg and caliber.
Final noise level 110-135 dBA. That's more than twice and as much as three times louder than slamming a hard bound book on my coffee table. We perceive loudness as having doubled with every 10dB. ( test case: wood table, 670 page hard bound book loudest hit was 98db from 2 feet)
What's that mean - A suppressed 9mm is twice as loud as a lawnmower or gas powered blower.
An unsuppressed firearm can rupture eardrums - and is louder than a Jet on takeoff from 25meters.
Small caliber - .22LR might only be 135dBA while most pistols used for self defense produce over 155dBA and Rifles around 165dBA.
For a typical polymer pistol like the Glock you will spend $1,260 to add a suppressor to your existing gun.
My 1911 it's closer to $1,600 or $1,700 some of that is the sights, most of it is getting a match barrel cut, threaded, crowned and fitted to my slide.
Buying the gun too? Add $500 for a Glock or $1,400 for my 1911
Background check & processing currently Takes about 8-9 months to get the paperwork back.
If you think that your typical criminal is going to do that you need to change your medication.
The Straw Man Knocked down and set on fire
Suppressors may be used on multiple firearms - depends on caliber and barrel threading. For example, a suppressor for a .45 ACP can be used on a .40 S&W or 9mm. A suppressor for a .308/7.62 will work on a .223/5.56 They may be somewhat less effective - I'll try to get more data on this as it is an important economic issue to purchasers.