What IS A Bump Fire Stock?

If you somehow haven’t noticed, one of the most controversial firearm accessories these days are “bump fire stocks,” which a few states have hastily outlawed along with a supposed impending (at the time of this writing) federal ban pending according to the current administration.

In the current political climate, many people want to see bump stocks banned.

Such devices were used to carry out the Oct. 1, 2017 massacre outside the Mandalay Bay hotel and casino in Las Vegas, by a shooter who took aim at the crowd from his hotel room. This has led to gun control advocates and elected officials who want to score points with those gun control advocates calling for a ban.

Whether Trump is serious or not remains to be seen. But we still get plenty of questions about bump fire stocks so a refresher with some accurate information is in order. 

For the total newbie, you’ve no doubt heard some exaggerated or otherwise conflicting information. Contrary to popular belief, a bump fire stock does not convert a semi-automatic rifle to a machine gun. It does, however, simulate it.

How does a bump stock do that? By means of a fairly simple mechanical trick. It does not a fully automatic weapon make, but it comes as close as you can without needing the license. 

A bump fire stock basically adds a buffer to the stock. A bump fire stock fully attaches to the buffer tube, but doesn’t fully attach to the lower receiver. Instead, most designs attach to the trigger guard (behind the trigger) via a hook on the left side of the grip. The allows the gun to travel inside the stock housing during the recoil cycle, but also acts as a buffer.

During a normal recoil cycle, the butt of the rifle is driven backward into the shooter. With the addition of the bump fire stock, the gun basically bounces back inside the stock housing itself, sliding forward until the trigger makes contact with the shooting hand. The trigger guard hook acts as a shelf for the trigger finger, allowing the shooter to keep their trigger finger stationary rather than having to continually pull the trigger for each shot.

The rapid fire effect is achieved by pushing the trigger with the trigger finger and holding the rifle to the shoulder while pulling with the support hand. A vertical fore grip makes the process easier.  

The push-pull action of the hands, combined with the travel of the rifle inside the stock results in the stationary trigger finger depressing the trigger much more rapidly than would otherwise be possible, creating a rapid fire effect in a rifle that is otherwise not select-fire capable. It’s still one round fired for each trigger pull, but the process happens more rapidly.

It’s fairly simple, really; a bump stock lets the rifle move back and forth which – combined with the push-pull movement and a stationary trigger finger – basically achieves faster fire without needing a permission slip. The ATF, for their part, looked at bump fire stocks years ago and certified them as legal under the law.  

However, there are a few things that you should know about bump-fire stocks prior to purchasing one (while you still can).

True select-fire-capable firearms actually operate at a much higher cyclic rate, meaning they fire many more rounds per minute than a bump stock-equipped rifle does. An M16/M4 with full automatic capability has a cyclic rate somewhere between 750 and 1000 rounds per minute, depending on specifications.

The typical bump fire stock will yield a cyclic rate of less than 300 rounds per minute, though it does so with a standard semi-automatic firearm.

Also, accuracy is severely impeded because you aren’t holding the rifle as you normally would to enable accurate fire. Bump fire stocks wouldn’t be viable in a military setting or law enforcement setting; these devices are basically for civilian enthusiasts to experience something like full auto at the range when they otherwise would be prohibited from doing so. 

Additionally – and this is important – sustained use of a bump fire stock can damage your rifle, most likely the barrel. A quality barrel can take more punishment than a lower quality barrel, but bear in mind that actual light machine guns for military use are designed for quick barrel changes to preserve accuracy and function. Your AR-15 wasn’t designed with that in mind. Thus, use with caution.  

One shouldn’t think of guns as “toys.” Recreational shooting is fun, to be sure, but guns, like any tool, can be dangerous if used irresponsibly or – worse – with malice. That said, bump fire stocks are basically “range toys” in the sense that they have no real practical purpose outside of basically burning through a lot of ammo. They’re made for fun, and for fun alone.

Unfortunately, a few found their way into the hands of a madman in October of 2017, resulting in the tragedy of the Las Vegas shooting. That was the only time one had been used in a crime in the eight-plus years that they’ve been available to the public. We may never know the full story behind the Las Vegas shooter, as his reasoning is now between him and whatever deity he conceived there to be.

For the rest of us, there’s a good possibility these devices will be banned by federal law in the near future, as bump stock bans receive both Republican and Democratic support and have not been strongly opposed by the National Rifle Association. They are already banned at the state level at the time of this writing in California, New Jersey, Vermont, Florida, Maryland, Hawaii and Washington state, and some selected cities. So now you know. 

comments

  1. avatar FedUp says:

    Such devices were used to carry out the Oct. 1, 2017 massacre outside the Mandalay Bay hotel and casino in Las Vegas.

    I wasn’t aware that had ever been proven.

    1. avatar Centuriator says:

      Yes, it was proven, and it was obvious listening to him shooting he had one going with extended capacity magazines. He jammed up several times.

      1. avatar Bearpaw says:

        Yawn. I just crawled out from under my rock. Nothing new here. Nite everyone.

      2. avatar Kroglikepie says:

        Really? You have the Metro or FBI reports that state as such? Because *NO ONE ELSE DOES* so that would be very interesting.

      3. avatar Michael says:

        He didn’t use a bump-stock, he used an illegally converted machine gun. The ATF already addressed this, but the media swept it under the rug because they wanted to demonize the bump-stock. The shooter did own bump-stocks, however none were used to carry out the shooting.

        1. avatar Charles says:

          Well America, once again, you have forgotten the meaning of two words; “right” and “infringement.”

        2. avatar Eric in Oregon says:

          Uh, no. It was bump-fire. It’s blatantly obvious.

      4. avatar Guy Tuten says:

        It was never proving to me that he used a bump stock it has never been proving that he was along up there and how do you account for the people seeing shooters on the ground to me nothing will ever be settled as long as the ATF and the FBI are involved I guess that’s because I remember WACO to good

  2. avatar jwm says:

    Bump fire stocks? They have the shoulder thingy that goes in, out. In, out. In, out. Not up.

  3. avatar Centuriator says:

    They are fun….on my son’s AK we actually outran the rifle’s ability to keep up with it a few times. But that’s about it…fun. Pretty darn worthless otherwise…unless…mayhem and firing into large crowds of people packed like sardines in a confined area.. from a concealed, elevated position.

    1. avatar BLAMMO says:

      I’ve never fired a bump stock and I’ve never tried to outrun the cycling rate of any of my ARs but I’m sure it’s possible. I don’t know if I could do it but I’ll bet Gerry Miculek can. I have done it with a 10/22 plenty of times. It’s easy to pull the trigger before it’s had a chance to reset.

      The natural cycling rate of a rifle is determined by its internal components. You might be able to increase the rate by changing the bolt, buffer, buffer spring, tweaking the gas system, etc. But I think everything has to be timed just right. Get it just a little wrong and you’ll get jams, FTFs, FTEs, etc. At best, you could be stuck with a bolt gun.

      With a little practice I would think you could come pretty close to a full-auto rate of fire without a bump stock. But I don’t have sponsors supplying me with bottomless boxes of ammo like Gerry Miculek.

  4. avatar Ralph says:

    Illegal in MA, and the penalty includes life in prison. Le that sink in. You can be imprisoned for life in MA for possession of a piece of plastic.

    1. avatar Cooter E Lee says:

      My brother lives up there in some $450,000 apartment that is smaller sq ft than my $26,000 POS Rental property mobile home on 3 acres. (You east coast intellectual elites ain’t as smart as you pretend to be.)

      I suggested he just throw a bump stick in a liberal politicians yard and call in an anonymous tip and a news crew to see what really happens. Shit, you don’t even have to use a real bump stock. Spray paint a super soaker flat black and write “bump stock” on it with a paint marker and that might be enough to finally get rid of fauxcahontas & co.

    2. avatar Endlesspath says:

      Curious how far MA has strayed from the U.S. Constitution – last time I checked, the 8th amendment to the U.S. Constitution stated explicitly:
      “Excessive bail shall not be required, nor excessive fines imposed, nor cruel and unusual punishments inflicted.”
      Life imprisonment for possession of a “bump stock”? Sounds very NAZI like~

  5. avatar TrueBornSonofLiberty says:

    What is a bumpstock? It’s a plastic firearm ACCESSORY!!! No more, no less. PERIOD.
    Note to the ATF and DOJ- make an appointment now. There’s 5 men, who’s names are Thomas, Alito, Roberts, Gorsuch and Kavanaugh. Who would like to see you, SOON.
    And beyond the unconstitutionality of banning them, it just might be your case that sets new precedent regarding Chevron Deference. 2 birds with one stone, you fascist cucks.

  6. avatar anarchyst says:

    Ban the bump stock, repeal the 1986 Lautenberg amendment that froze the number of machine guns for civilians, and re-open the NFA registry for new machine guns. Now THAT is a “compromise” that I could go along with…

    1. avatar TrueBornSonofLiberty says:

      I’d support that in the meantime. Until we can repeal the NFA. And then the GCA of 1936.

    2. avatar Disgruntled Floridian says:

      That would be backdoor gun registration since a lot more people understand the NFA and how to get NFA guns than they would have pre-internet. But I think it would be a decent compromise before we can move onto the NFA itself. Luckily boating accidents don’t care if your gun is registered or not.

    3. avatar Cz Rider says:

      Yeah, I see that getting abused to add semi-auto rifles capable of being modified to full auto (AKA all of them) pretty quickly. There will mysteriously be a mass shooter who happens to be really good at belt loop bump fire, and the halls of Congress will echo with the idiotic wails of people screaming about doing something. I don’t see a point in anything but loud and fierce opposition on all fronts when we’re dealing with a group that is clearly using every “compromise” they can wring out of us as a launching point for their next power grab.

      1. avatar TrueBornSonofLiberty says:

        Well, I think that avenue of banning semi-autos died on the vine during the Kavanaugh judicial hearings. If you followed thems closely, you would’ve seen that Kavanaugh essentially proclaimed ALL semi autos Constitutional, including ARs in particular. He cited “common usage” as the reason. It’s IMPOSSIBLE for anyone to argue semi autos aren’t the most ubiquitous platform for firearms. Kennedy’s uncertainty was the primary reason the court hasn’t been taking these cases, in my opinion. Without being fairly certain of the outcome, neither side was willing to grant cert. I think we’ll know pretty quickly which direction things will be going based on if/when the court starts taking, or refusing to take cases. If the court starts agreeing to take cases, it’s all over for the filthy, anti-American, gun grabbing traitors. And yes, I’m holding my breath, because I believe our Founders knew what they were doing and that we’ve finally assembled 5 Americans who will honor them (yes- I’ll admit that Roberts worries me a little). And as far as Ginsberg is concerned, May she Rest In Peace. Soon.

    4. avatar Kroglikepie says:

      HUGHES, not Lautenberg. Lautenberg is the domestic abuse ban. Shit, we rib the commies for not knowing anything about gun laws, and you go off on this ignorant tangent.

  7. avatar doesky2 says:

    The typical bump fire stock will yield a cyclic rate of less than 300 rounds per minute, though it does so with a standard semi-automatic rifle.

    Not!
    Here is a bone stock Colt 6920 with an original crappy trigger that’s running right in the middle of the 750-900 rating for an M4.

    1. avatar doesky2 says:

      Before someone asks…..
      The 33 rounds was the leftover from a 40rd Pmag.
      It runs a tad faster with a 30rd mag.

      1. avatar Cz Rider says:

        That actually illustrates the reason why this whole issue is so confused and potentially dangerous to our rights. Practically speaking, that semi-auto rifle has the same cyclic rate as a machine gun – it just has a lower achievable rate of fire for the average person because they can’t pull the trigger 750 times in a minute.

        It’s confused because the average person you’d explain that to would probably wonder why anyone cares about bump stocks at all then since it’s perfectly possible to get the same effect unassisted through practice. It’s dangerous because it could also be used as justification for arbitrary rate of fire limits and a ban on anything capable of breaking the shooting speed limit (AKA all current designs). I’ve seen people say that wouldn’t happen in places like Florida where these nonsense laws already exist, but I’d refer you to the SAFE act for an example of an arbitrary government ban on something that’s largely a matter of user preference otherwise (mag capacity).

  8. avatar Chris T from KY says:

    Sadly many in the “gun Community” Support a bump stock ban. Just as they support the NFA and the Hughes Amendment. They just won’t admit it in a public forum.

    They are against ordinary citizens having inexpensive rapid-fire weapons. The similar weaponry, and more expensive , that civilian police or the federal military have.

    And then those same people will hate on the High Point company and Hi Point gun owners???

    The real purpose behind the 1968 Gun Control Act was to make handguns more expensive and they were successful.

    1. avatar el Possum Guapo ect. says:

      Actually for the price I don’t think you can buy a better sidearm then a Hi Point.

      1. avatar JR says:

        That’s true, because at that price you cant buy ANY other firearm.

  9. avatar TruthTellers says:

    NFA states that a machine gun is a gun that fires more than one round per one pull of the trigger, bump stocks pull the trigger each time a round is fired, it’s not a machine gun, so there’s no illegality involved; everything is done in accordance to the NFA act.

    States can ban them, but the ATF must act according to a law. If the words in federal laws can be ignored, then no law means anything.

    This is all about establishing how fast a civilian is allowed to fire an amount of rounds in a given amount of time. Thing is, that can’t be done, people are different, they shoot at different speeds. They can talk about limiting magazine sizes that do nothing to stop a mass shooting, they can regulate bump stocks that can be easily made in the future with a 3D printer or today in a basement or garage, but the simple fact is that none of it works.

    So, the next logical step is just to go after semi-automatics. They’ve even come up with a new, fake news term called Fully Semi-Automatic to be carried by the stupid masses.

    Trump and Republicans will go on with bump stock regs because their alternative argument is the same one I just made about their ease of manufacture, how they’re not much more deadly than a standard AR15. To not ban bump stocks will make it look like they want more people to be murdered. The stupid masses will take that and say it’s all semi-automatics that have to go and all the Republicans/NRA who are accessories to murder.

    The thing is that whether bump stocks get banned under Trump or not doesn’t mean crap because as soon as the D’s take over, they’ll be gone anyway, but to not ban them under Trump just motivates the stupid masses even more and instead of a Blue Wave, we’d have a Blue Tsunami that takes both House and Senate.

    The only hope is SCOTUS starts taking up more 2A cases and affirming that the 2nd protects magazines, ammo, bump stocks, and other things to the extent that no laws passed can take away more of the 2nd amendment.

    1. avatar RMS1911 says:

      “States can ban them,” no they can’t they have no say so at all it’s strictly federal just like immigration.(thanks Obama for the reinforcement of the supremacy clause)
      The feds can’t ban them because of article 1 section 9, article IV, article VI and the second amendment.
      The states can’t ban them because of article 1 section 10,article IV, article VI and the second amendment.
      Article 1 sections 9 & 10- ex post facto
      Article IV – equal protection clause
      Article VI – supremacy clause
      Second amendment – rtkaba
      Now if we only had some justices who read and understand the Constitution says exactly what is written not some hidden code or intentions.

  10. avatar el Possum Guapo Standartenfuher " they think we're making pizza's Oberst von Burn says:

    My beloved President says “,bumpstocks turn rifles into machininguns, we can’t have that” Congress be damned my beloved President is writing them off…..What’s getting in my beloved Presidents way of MAGA is all the laws, he said so himself.

  11. avatar Green Mtn. Boy says:

    Vermont had a period to turn in your B F stocks before the law took affect Oct. 1 st. and had a grand total of just 2 turned in,not many owned by Vermonters or not willing to part with their property ,law or not.

  12. avatar Jay in Floriduhhh says:

    The lakes in Vermont must be full of bump stocks that fell off their ARs .
    Also maybe a handful of 10-22s.
    I lost my crank and inertia trigger for the Glock I dont own Sept 31st. Must be in the canal behind my house???

  13. avatar Peter Schiavo says:

    Bumpstocks have two purposes: range toy and indiscriminately firing into large defenseless crowds at a distance. It turns an accurate rifle into an inaccurate bullet hose.

    We’re supposed to be a country of rifleman, prepared to defend against all enemies, foreign and domestic. How does the bumpstock help to fulfill that role? In terms of the second amendment, it’s easier to defend the ownership of live fragmentation grenades than bumpstocks.

    1. avatar No one of consequence says:

      No.

    2. avatar uncommon_sense says:

      Peter Schiavo,

      A bumpstock could be very important and incredibly useful for close-quarters combat. Suppose I am defending a pinch point (like my front door) where five armed attackers are trying to pile-in just 20 feet away: being able to push out 7 rounds per second into that incoming mass of attackers would be incredibly useful — even with the limited accuracy of a bumpstock platform.

      And that is the entire point of eliminating firearm limitations: different people will find particular features or functions to be valuable for different reasons in different situations. I don’t tell the next person which power tools or construction equipment are utilitarian — neither should they tell me. And the same applies to firearms.

      1. avatar Peter Schiavo says:

        So you’re carrying a rifle around that 100% of the time will be very inaccurate at all ranges in order to fire a few extra rounds in the unlikely event that your assailants helpfully bunch up in close quarters? Wouldn’t a regular AR-15 do the exact thing, but also be useful for long range shooting?

        1. avatar That One Guy says:

          Attaching a bump stock to an AR doesn’t make it inaccurate 100% of the time. It decreases accuracy when it’s being used to (poorly) simulate automatic fire. For every other shot that you aren’t using your off hand to pull the gun away from your shoulder, your AR acts exactly like every other AR on the planet.

          To this end, it’s a legal version of the select fire military options. Fairly accurate single shot, somewhat inaccurate multi-shot. Sometimes a bullet hose is the exact right tool for the job. Sometimes a well-placed single shot is the right tool for the job. A bumpstock allows one rifle to function as both tools.

  14. avatar GunnyGene says:

    The danger to the RKBA with a successful ban on this and similar accessories (binary triggers, and so forth) that the left claims increase “lethality” of the firearm, is that the same argument – increased lethality – can and will be used to ban other accessories such as scopes.

    Improved accuracy at longer ranges equates to improved lethality , which is what the anti’s basic complaint is.

    It’s the precedent being set by the “rate of fire” ban that is the most dangerous aspect of this entire kerfuffle.

  15. avatar GunnyGene says:

    To add to my last: The ability to put accurate fire on target at ranges in excess of 500 yds has always been more desirable and well regarded than simply spray and pray at short range.

    Carlos Hathcock wasn’t the only sniper in Vietnam.

  16. avatar Matthew the Oilman says:

    Once again I point out the politics of the bell curve. Rush Limbaugh,who is on the right side of the bell curve is in favor of banning bump stocks, apparently. I don’t hear a lot of second admendment purists calling in to tell him ( politely and intelligently) why he is wrong. I can not do it, I can listen, but calling the largest radio talk show in North America cannot be done while working.
    And you can forget about the regular news media , they want to ban all guns.
    And I have yet to see polling on banning bump stocks!
    But you say, we have the second admendment, that only means anything as long as 70% of the people who vote want it. Just remember that.

  17. avatar Gideon Rockwell says:

    Even though these stocks are not to my taste, I don’t believe they need to be banned. In my opinion they are just one more way to burn a lot of ammo really fast with little effect. I have fired a number of select fire arms and find if not firing semi-auto, the three shot burst is the next most accurate firing mode. With a little practice, once you get to know the weapons recoil pattern in three shot burst, you can get some pretty accurate triple taps out to 50 yards. With the H&K MP5 you can actually get some pretty decent 3 round burst groups out to 100 yards when using really good optics.

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