Through research and community posts, you’ll find many acronyms and phrases used to describe various suppressor parts and companies. Jargon is also used often when discussing suppressor design, specifications, and other elements. This alphabetically organized glossary defines most terms and shorthand used in the Form 1 build community.

  • 24 TPI: A measurement of threads per inch, common for tube thread adapters and end caps.
  • 300BO/BLK/AAC: 300 AAC Blackout, a rifle cartridge developed for both 0suppressed subsonic and supersonic performance.
  • 50-degree: A common angle for straight conical storage cups.
  • 60-degree: A common angle for straight conical storage cups.
  • Ablative: An evaporating liquid gel or foam used to reduce FRP, or first-round pop, by replacing oxygen in a suppressor’s blast chamber.
  • Al, Aluminum: A common, affordable alloy used in tubes and solvent traps for firearms chambered in subsonic or pistol cartridges.
  • Alignment rod: A rod used to verify the bores of all end caps, thread adapters, and baffles are aligned to prevent a baffle or end cap strike.
  • Ask the Experts: A function on the E-Forms ATF dashboard used to communicate with ATF agents who process Form 1 applications.
  • ASR, Active Spring Retention: A quick attach / detach suppressor mounting system and type of thread measurement developed by Silencer Co.
  • ATF, Alcohol, Tobacco, Firearms: The bureaucratic federal agency that should not exist, which regulates suppressors.
  • Aztec: A nickname for stepped solvent trap storage cups.
  • Baffle: The dividers or fixtures, often conical in shape, used inside a suppressor to attenuate a firearm’s muzzle blast.
  • B-Cell: A tube measurement that is most often 1.313” OD by 1.150” ID.
  • Blast Baffle, BB: The first baffle in a suppressor, often made from stainless steel, which absorbs the most heat and pressure near the muzzle.
  • Blast Chamber, BC: The initial chamber present inside a suppressor that allows gas to expand as it first leaves the muzzle, before traveling through the baffles and spacers toward the end cap.
  • Booster: A device used to on pistol suppressors which temporarily removes the weight of a suppressor from the barrel using a spring, allowing the pistol to cycle rounds reliably.
  • Bore: The hole drilled through the center of end caps, thread adapters and suppressor baffles which allows a bullet to pass through.
  • Brake: A muzzle brake or muzzle device which different suppressor mounts install upon.
  • C-Cell: A tube measurement that is most often 1.23” OD by 1.03” ID.
  • Cerakote: A high-temperature coating like paint, often used to coat a suppressor.
  • Cherry Bomb: A type of muzzle device that acts as a muzzle brake.
  • Clip: A cut made on the bore of a baffle to improve a suppressor’s performance.
  • Clocking: The act of aligning the clips inside a suppressor to reduce POI shift.
  • Cone: A nickname for a solvent trap cup that has been modified by the end-user to function as a makeshift baffle used inside a suppressor. They are conical in shape.
  • Cover Letter: A letter the ATF provides Form 1 applicants to mail fingerprints for the application’s approval.
  • Cup: A nickname for a solvent trap cup that has been modified by the end-user to function as a makeshift baffle used inside a suppressor. They are conical, radial, or stepped.
  • D-Cell: A tube measurement that is most often 1.500” OD by 1.360” ID.
  • DHC, Double-Hybrid Clip: A type of clipping style once used on discontinued RSC solvent trap cups, which are described further below.
  • Direct thread: A type of suppressor mount which threads directly to the muzzle of a firearm. No brake or muzzle device is used.
  • Distal Space, Distal Chamber: The chamber, or size of the chamber, between the last baffle and the end cap in a suppressor.
  • DM, Diversified Machine: A solvent trap manufacturing company.
  • Double Clip: A type of clip, symmetrical or asymmetrical, applied to the bore of a baffle to improve a suppressor’s performance.
  • Duracoat: A type of high-temperature firearm paint often applied to a suppressor.
  • E-Forms: The ATF’s web-based dashboard used by Form 1 applicants to apply to make a suppressor.
  • End cap: The cap which seals the end of a suppressor, with a center-bored hole for a bullet to pass through.
  • FFL, Federal Firearms Licensee: A licensed firearm or suppressor manufacturer.
  • F1, Form 1: The type of application one must submit to the ATF to build a homemade suppressor.
  • F4, Form 4: The type of application one must submit to the ATF to buy a commercial suppressor.
  • Freeze Plug: An automotive plug used to fill the sand casting core holes on a water-cooled engine, often modified by the end-user to function as a makeshift suppressor baffle; these provide generally poor performance in suppressors but are affordable and simple to modify.
  • FRP, First-Round Pop: The loudest sound reported as the first round passes through a suppressor. This “first pop” is louder than subsequent shots because of oxygen present in the suppressor. As oxygen is burned by excess gunpowder, subsequent shots become quieter.
  • GA, Griffin Armament: A suppressor company that manufacturers muzzle devices which are popular among Form 1 builders.
  • Gemtech: A popular suppressor company. Many Form 1 builders work to fabricate suppressors capable of meeting or exceeding the performance of commercial suppressors like Gemtech’s.
  • Grade-9: A grade of titanium capable of withstanding the high heat and pressure generated inside a suppressor. Most often used to fabricate solvent trap cups and baffles in centerfire rifles.
  • HIT, Hawk Innovative Tech: A solvent trap manufacturer.
  • ID, Inner Diameter: The inner diameter of a tube.
  • Inconel: a special lightweight, temperature-resistant alloy used by commercial suppressor makers.
  • Jig: a device used with a drill press or milling machine to drill a suppressor baffle’s bore.
  • JR, JR Machine Pro: A solvent trap manufacturer.
  • K-cup, K-baffle, or simply K’s: A type of complex baffle most often used for subsonic and pistol cartridges.
  • Keymo: A quick-attach muzzle device adapter often used for commercial and homemade suppressors. Compatible with DeadAir Silencers’ muzzle devices.
  • Knurled: a pattern lasered or fabricated into a tube to provide extra grip when tightening.
  • Laminar Flow: The flow of high-pressure gasses through a suppressor.
  • Lathe: a machine often used to cut and drill suppressor baffles and spacers, also called skirts.
  • Liberty: A silencer company that manufacturers popular muzzle devices and quick-attach mounts for suppressors.
  • Lucid Machine Co: A solvent trap manufacturer.
  • Mill: A machine often used to cut baffle clips and drill suppressor baffles.
  • MMW, Muted Machine Works: A solvent trap manufacturer.
  • Monocore: A type of suppressor internal that uses a single piece of milled alloy instead of spacers and individual cups, cones, or baffles.
  • MP, Maverick Precision: A solvent trap manufacturer.
  • OAL, Overall Length: The total length of a suppressor.
  • OD, Outer Diameter: The external diameter of a tube or baffle.
  • OTB, Over-the-Barrel: A type of suppressor that covers part of a barrel past the muzzle when installed, reducing total length of the firearm when compared to a conventional suppressor.
  • POI, Point of Impact: The point where a round impacts a target relative to point of aim. POI can be shifted when a suppressor is used, especially if asymmetrical or single clips are used on baffles.
  • Q plan B: A type of muzzle device adapter for a suppressor.
  • QB, Quiet Bore: A solvent trap manufacturer.
  • QD or Quick-Detach: A type of suppressor adapter that allows for quick installation and removal without direct threads.
  • Quell, or Quelltech: A solvent trap manufacturer.
  • Radial: A type of conical solvent trap cup or suppressor baffle that is sloped.
  • Raven: A type of solvent trap tube size designed by Maverick Precision.
  • RSC, Rusty’s Cans: A discontinued type of solvent trap storage cup developed an individual named Rusty. This design was adopted and modified by Super Precision Concepts, labelled the SPC Pro.
  • SDTA, SD Tactical Arms: A solvent trap manufacturer.
  • Skirt. A nickname for a suppressor baffle’s or solvent trap cup’s spacer.
  • SiCo, Silencer Co: A commercial suppressor manufacturer.
  • Single Clip: a type of clip or cut made on the bore of a baffle to improve disruption of laminar flow, which improves sound suppression.
  • Solvent Trap: A sealed tubular cleaning device that contains storage cups or “traps”, which attaches to the muzzle of a firearm to safely contain solvents and harmful chemicals often used to clean a firearm’s bore and rifling.
  • SOT, Special Occupancy Tax: A designation required for some FFLs to manufacturer Class III firearms.
  • Spacer: A piece of thin tube used to separate the storage cups in a solvent trap, or the baffles in a suppressor.
  • SPC, Super Precision Concepts: A solvent trap manufacturer.
  • SS, Stainless Steel, Silencer Shop: A type of alloy popular in blast chambers, blast baffles, and suppressors that fire centerfire cartridges. An acronym also used to describe Silencer Shop, a popular online Form 1 and Form 4 suppressor dealer.
  • Stack: The complete design, including baffles and spacers, of a suppressor’s internals.
  • Step, or Stepped Cone: A type of solvent trap storage cup that incorporates small steps on its conical face, which may be modified by the end-user to function as a suppressor baffle. Some believe the steps on a modified stepped cone may improve disruption of laminar flow.
  • Storage Cup, Storage Divider: A solvent trap item designed to capture and contain harmful solvents and chemicals inside a firearm solvent trap, which may be modified an the end-user to function as a makeshift suppressor baffle.
  • Sub(sonic): A rifle or pistol cartridge that travels below 1,125 feet per second.
  • Super(sonic): A rifle or pistol cartridge that travels over 1,125 feet per second.
  • Surefire: A commercial suppressor manufacturer.
  • STD, Solvent Traps Direct: A solvent trap manufacturer.
  • Talon: A type of solvent trap tube designed by Maverick Precision.
  • Taper Mount: A type of quick-attach design used in muzzle devices and thread adapters.
  • Thread Adapter: A type of suppressor end cap that allows a suppressor to be fitted to a muzzle device.
  • Three-lug: A type of quick-attach muzzle device and thread adapter system popular on suppressors.
  • Ti, Titanium: A high-strength, lightweight alloy used in solvent traps and suppressors.
  • Totality: A discontinued brand of solvent trap cups.
  • Tube: A solvent trap tube.
  • VSR, Valve Spring Retainer: Often used on high-performance engines, these alloy fixtures can be modified and used as makeshift suppressor baffles.
  • Wait time: The average time it takes for a Form 1 application to be approved by the ATF.
  • Wall thickness: The overall thickness of a tube or alloy.
  • Weep hole: Holes that were once drilled into military-issued suppressor baffles to allow solvents and liquids to drain. This is no longer a popular design element in most modern suppressors.
  • Wet: The act of applying oil or liquid to the inside of a suppressor to improve its performance.
  • Wipe: A disposable soft cloth or polypropylene patch placed inside a suppressor to temporarily improve its performance.
  • WTT, White Trash Tactical: A solvent trap manufacturer.