Bump fire

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A Slidefire bump fire stock on a WASR-10 rifle

Bump fire is the act of using the recoil of a semi-automatic firearm to fire shots in rapid succession, which simulates the rate of fire of a fully automatic firearm.

Bump fire gunstocks are of varying legality in the United States. The Department of Justice announced a plan on March 23, 2018 to classify bump stocks as "machine guns" and effectively ban them nationwide under existing federal law.[1] If the rule becomes final, existing bump stocks would be required to be destroyed or surrendered by both manufacturers and individual owners.[2]

On April 17, 2018, Slide Fire Solutions, the sole holder of the bump stock patent, announced that it would cease production of bump stocks as of May 20, though they did not state whether this was a temporary or permanent measure. It has temporarily suspended production before.[3]


Essentially, bump stocks allow rapid fire by "throwing" the trigger against one's finger (as opposed to one's finger pulling on the trigger) thus allowing the firearm's recoil to actuate the trigger.

The bump firing process involves bracing the firearm with the non-trigger hand, releasing the grip on the firing hand (leaving the trigger finger in its normal position in front of the trigger), pushing the firearm forward with the non-trigger hand in order to apply pressure on the trigger from the finger, and keeping the trigger finger stationary. During a shot, the firearm will recoil ("bump" back) and the trigger will reset as it normally does; then, the non-trigger hand pulls the firearm away from the body and back to the original position, pressing the trigger against the stationary finger again, thereby firing another round when the trigger is pushed back.

Normally, a rifle is held securely and firmly against the shoulder, but the loose shoulder hold that allows the weapon's recoil to aid trigger depression affects accuracy in a way that is not encountered with firearms that are designed for select-fire.

A similar method can be employed with semi-automatic pistols, in which one hand holds the grip, two fingers of the other hand are placed in the trigger well, and then the grip hand shoves the firearm forward while the trigger fingers remain stationary. With revolvers, rapid fire can be achieved by using two trigger fingers firing offset.


All these techniques greatly degrade the accuracy of the firearm. The techniques trade accurate, aimed fire for an increase in the firearm's rate of fire. The inaccuracy renders the practice uncommon for precision target shooting, but is increasingly popular for applications where volume of fire is favored over accuracy. None of these techniques fire more than one round with a single trigger pull; rather they compensate for biomechanical limitations associated with how fast a finger can repetitively pull the trigger.

With bump firing, it is common to use all the rounds in the firearm's magazine, but it becomes easy to create a stoppage as the cycling of all semiautomatic firearms requires the bolt to move against the stationary firearm (low-mass semiautomatic pistols suffer from the same problem due to "limp wristing"). The bolt must complete the stroke against the spring, and that doesn't happen if both the bolt and spring are moving rearward. Non-bump fire rifles can suffer the same failure from fouling or for undercharged ammunition. Blanks also can cause these failures. Additionally, it is possible that if a gun is bump-fired too fast, then the hammer will be released before the bolt closes. This will either cause the hammer to "ride" the bolt carrier without firing the chambered round or cause the firearm to slamfire.

Bump fire stocks[edit]

A bump stock permits the trigger (red) to be held down when the receiver moves forward, being reset each round by receiver recoil. This allows semi-automatic firearms to somewhat mimic fully automatic weapons
Legality of bump stocks in the United States
  Bump stocks legal
  Legality unclear
  Bump stocks illegal

Bump fire stocks are gunstocks that are specially designed to make bump firing easier, which allows semi-automatic firearms to somewhat mimic the firing speed of fully automatic weapons.[4] Bump fire stocks can be placed on a few common weapon platforms such as the AR or AK families. They can achieve rates of fire between 400 to 800 rounds per minute depending on the gun.[5] As of 2018, bump fire stocks in the United States may sell for around $100 and up, with prices increasing due to potential regulation.[6][5]

Slide Fire Solutions, the inventor, patent holder, and leading manufacturer of bump stocks, suspended sales after bump stocks were used in the 2017 Las Vegas shooting and resumed sales a month later.[7][8] On May 20, 2018, Slide Fire Solutions halted sales and production of its products.[3]

Regulatory status in the United States[edit]

The ATF ruled in 2010 that bump stocks were not a firearm subject to regulation and allowed their sale as an unregulated firearm part.[5][9][10] In the 2017 Las Vegas shooting, twelve bump fire stock devices were found at the scene.[11] The National Rifle Association stated on 5 October 2017, "Devices designed to allow semi-automatic rifles to function like fully-automatic rifles should be subject to additional regulations", and called on regulators to "immediately review whether these devices comply with federal law".[12] The 2017 shooting generated bipartisan interest in regulating bump stocks.[13] On 4 October 2017 senator Dianne Feinstein introduced a bill to ban bump stocks,[5] but as of November 3, 2017, no Congressional action had resulted. Instead, on February 20, 2018, President Trump instructed the ATF to issue regulations to treat bump stocks as machineguns.[14] The Department of Justice on March 23, 2018 announced a plan to change the regulatory status of bump stocks. The proposed change would classify bump stocks as "machine guns" and effectively ban the devices in the United States under existing federal law.[1] If the rule becomes final, people would be required to destroy or surrender existing devices. A notice of proposed rulemaking was issued by the ATF on March 29, 2018, and opened for public comments.[15][2]

Sale of bump stocks has been illegal in California since 1990. They were banned in New York with the passage of the NY SAFE Act in 2013. In his final day as governor in January 2018, New Jersey Governor Chris Christie signed legislation making the gun accessory illegal in New Jersey.[16] The device's legal status is unclear in Connecticut, Michigan, Minnesota, Puerto Rico, and Washington, D.C.[17] Massachusetts banned bump stocks after the 2017 Las Vegas shooting.[8]

On March 9, 2018, after the 2018 Stoneman Douglas High School shooting, the state of Florida enacted SB 7026, which, among other things, banned bump stocks.[18][19] Some parts of the bill took effect immediately, but the portion banning bump stocks took effect October 1, 2018.[20] Vermont passed a similar law in 2018.[21] Delaware,[22] Hawaii,[23] Maryland,[24] Washington[25] followed suit.

Some states that do not ban bump stocks may have localities that ban them, such as Northbrook, Illinois,[26] Boulder, Colorado,[27] etc.

Patent infringement suit[edit]

Slide Fire Solutions filed suit against Bump Fire Systems for infringement of its patents on bump stock designs in 2014.[28] The suit alleged that Bump Fire Systems infringed eight US Patents, for example, United States Patent No. 6,101,918 entitled "Method And Apparatus for Accelerating the Cyclic Firing Rate of a Semi-Automatic Firearm"[29] and United States Patent No. 8,127,658 entitled "Method of Shooting a Semi-Automatic Firearm".[30] The suit was settled in 2016, resulting in Bump Fire Systems ceasing manufacture of the product in contention.[31]

Other lawsuits[edit]

Survivors of the October 1, 2017 Las Vegas shooting sued bump stock patent holder and manufacturer Slide Fire Solutions, claiming the company was negligent and that they deliberately attempted to evade U.S. laws regulating automatic weapons: "this horrific assault would not and could not have occurred, with a conventional handgun, rifle, or shotgun, of the sort used by law-abiding responsible gun owners for hunting or self defense."[3]

Public opinion[edit]

Recent polls show public support for a bump stock ban. Immediately following the 2017 Las Vegas Shooting 72% of registered voters supported a bump stock ban, including 68% of Republicans and 79% of Democrats.[32] A 2018 poll found 81% of American adults supported banning bump stocks with a margin of error of +/- 3.5%.[33] A different poll around the same time found 56% of American adults supported banning bump stocks with a margin of error of +/- 4%.[34]

See also[edit]


  1. ^ a b "Sessions effectively bans bump stocks". Axios. Retrieved 2018-03-24.
  2. ^ a b Horwitz, Sari (2018-03-23). "Justice Department proposes banning bump stocks, branding them machine guns". Washington Post. ISSN 0190-8286. Retrieved 2018-03-24.
  3. ^ a b c Romo, Vanessa (April 18, 2018). "Bump Stock Manufacturer Is Shutting Down Production". NPR. Retrieved July 24, 2018.
  4. ^ CNN, Nicole Chavez. "Bump stock: The device found on Las Vegas shooter's guns". CNN. Retrieved 2017-10-06.
  5. ^ a b c d "The "bump stocks" used in the Las Vegas shooting may soon be banned". The Economist. 6 October 2017.
  6. ^ Berr, Jonathan. "Bump stock prices soar ahead of potential federal ban". CBS News. CBS News. Retrieved 11 April 2018.
  7. ^ Mann, Brian (November 7, 2017). "Bump Stock Manufacturer To Resume Sales Of Controversial Device". All Things Considered. NPR. Retrieved July 24, 2018.
  8. ^ a b Lartey, Jamiles (November 7, 2017). "Leading bump stock maker briefly makes product available again". The Guardian. Retrieved July 24, 2018.
  9. ^ Krouse, William J. (October 10, 2017). Gun Control: "Bump-Fire" Stocks (PDF). Washington, D.C.: Congressional Research Service. Retrieved 12 December 2017.
  10. ^ Peck, Sarah Herman (April 11, 2018). ATF’s Ability to Regulate “Bump Stocks” (PDF). Washington, DC: Congressional Research Service. Retrieved 18 April 2018.
  11. ^ "Las Vegas Shooting: Gunman's Rifle Had 'Bump Stock' to Make It Rapid-Fire Weapon". The New York Times. Retrieved 3 October 2017.
  12. ^ "Las Vegas shooting: NRA urges new rules for gun 'bump-stocks'". BBC News. 2017-10-05. Retrieved 2017-10-05.
  13. ^ Connolly, Griffin; Connolly, Griffin (5 October 2017). "House GOP Shows 'Overwhelming' Interest in Bipartisan Bump Stock Bill" – via www.rollcall.com.
  14. ^ Carter, Brandon (2018-02-20). "Trump to take steps to ban bump stocks". The Hill. Retrieved 2018-02-20.
  15. ^ "Regulations.gov". www.regulations.gov. Retrieved 2018-03-31.
  16. ^ "N.J. bans gun device used in Las Vegas shooting after Christie signs bill". NJ.com.
  17. ^ "Where are bump-fire stocks illegal? Feds, states weigh bans after Las Vegas shooting". CBS News.
  18. ^ CNN, Athena Jones, Darran Simon and Carolyn Sung,. "Florida Senate passes bill raising age to buy guns". CNN. Retrieved 2018-03-08.
  19. ^ "The NRA sued to block Florida's new gun law hours after it was passed". Vox. Retrieved 2018-03-13.
  20. ^ "BREAKING - Florida Republicans Pass Gun Control Bill - The Truth About Guns". The Truth About Guns. 2018-03-07. Retrieved 2018-03-13.
  21. ^ "Vermont Governor Signs State's First Significant Gun-Control Laws | National Review". National Review. 2018-04-12. Retrieved 2018-04-13.
  22. ^ "Delaware's bump stock ban to take effect after buyback events". WHYY. Retrieved 2018-11-22.
  23. ^ Press, Associated. "Hawaii lawmakers pass bump stock ban". Retrieved 2018-04-28.
  24. ^ "Ban On 'Bump Stocks' Among New Gun Regulations In Maryland | WAMU". WAMU. Retrieved 2018-04-28.
  25. ^ "Inslee signs bill to ban bump stock devices like those used in the Las Vegas shooting | Governor Jay Inslee". www.governor.wa.gov. Retrieved 2018-04-28.
  26. ^ Kukulka, Alexandra. "Northbrook bans bump stocks throughout village, concealed carry in businesses where alcohol consumed". chicagotribune.com. Retrieved 2018-06-22.
  27. ^ Gstalter, Morgan (2018-05-17). "Boulder City Council votes to ban assault-style weapons". TheHill. Retrieved 2018-06-24.
  28. ^ Case 3:14-cv-03358-M Document 1 Filed 09/16/14, retrieved 3 October 2017
  29. ^ US patent 6101918, William Akins, "Method and apparatus for accelerating the cyclic firing rate of a semi-automatic firearm", published Aug 15, 2000, assigned to William Akins 
  30. ^ US patent 8,127,658, Jeremiah Cottle, "Method of shooting a semi-automatic firearm", published Mar 6, 2012, assigned to Slide Fire Solutions, Inc. 
  31. ^ "Slide Fire Solutions forces Bump Fire Systems Out Of Business", Guns.com
  32. ^ Sanger-Katz, Margot; Bui, QuocTrung (October 12, 2017). "A Bump Stock Ban Is Popular With the Public". Retrieved July 24, 2018.
  33. ^ Khalid, Asma (March 2, 2018). "NPR Poll: After Parkland, Number of Americans Who Want Gun Restrictions Grows". Morning Edition. NPR. Retrieved July 24, 2018.
  34. ^ "Poll: Support for stricter gun laws rises; divisions on arming teachers". CBS News. February 23, 2018. Retrieved July 24, 2018.