Guedes v. Bureau of Alcohol, Tobacco, Firearms and ExplosivesGuedes v. Bureau of Alcohol, Tobacco, Firearms and Explosives
- Reporters:
- ,
- Before:
- Srinivasan, Wilkins, Edwards
The Bureau interpreted “machine gun,” as defined in the National Firearms Act and Gun Control Act, to extend to bump stocks. Plaintiffs initially moved for a preliminary injunction to stop the rule from taking effect, which the District Court denied, and a panel of this Court affirmed. At the merits stage, the District Court again rejected Plaintiffs’ challenges to the rule under the Chevron framework. See Chevron, U.S.A., Inc. v. Natural Resources Defense Council, Inc., 467 U.S. 837 (1984). The central question on appeal is whether the Bureau had the statutory authority to interpret “machine gun” to include bump stocks. Employing the traditional tools of statutory interpretation, we find that the disputed rule is consistent with the best interpretation of “machine gun” under the governing statutes. We therefore affirm.
I.
A.
Congress enacted the National Firearms Act in 1934 to regulate the sale of particular firearms, including machine guns. Initially, the Act defined a “machine gun” as “any weapon which shoots, or is designed to shoot, automatically or semiautomatically, more than one shot, without manual reloading, by a single function of the trigger.” Pub. L. No. 73-474, § 1(b), 48 Stat. 1236, 1236 (1934). In 1968, Congress removed “or semiautomatically” and expanded the definition to include:
the frame or receiver of any such weapon, any combination of parts designed and intended for use in converting a weapon into a machinegun, and any
combination of parts from which a machinegun can be assembled.
Pub. L. 90-618, 82 Stat. 1213, 1231 (1968). Congress charged the Attorney General with enforcement of the National Firearms Act, who in turn delegated enforcement authority to the Bureau.
With the Gun Control Act of 1968, Congress incorporated the National Firearms Act‘s definition of “machinegun” and strengthened its prohibitions on firearm sales and licensing.
In 2006, the Bureau determined that certain bump stock devices—ones that harnessed energy from an internal spring‘s recoil, like an Akins Accelerator—qualified as machine guns under both Acts. See ATF Rul. 2006-2. Between 2008 and 2017, however, the Bureau issued ten letter rulings in which it concluded that devices relying on both the recoil energy and the shooter‘s constant forward pressure were not machine guns. These weapons fired multiple shots with a “single pull of the trigger,” but in the Bureau‘s view did not operate
In the aftermath of the Las Vegas shooting, then-President Trump and Congress urged the Bureau to revisit its position on bump stocks. Department of Justice Announces Bump-Stock-Type Devices Final Rule, Dep‘t of Just. (Dec. 18, 2018), https://www.justice.gov/opa/pr/department-justice-announces-bump-stock-typedevices-final-rule, J.A. 21–22. Following a notice of proposed rulemaking, see Bump-Stock-Type Devices, 83 Fed. Reg. 13,442 (Mar. 29, 2018), the Bureau issued a final rule reversing its earlier position that only bump stocks with internal springs qualified as machine guns under the National Firearms Act and Gun Control Act. Bump-Stock-Type Devices, 83 Fed. Reg. 66,514, 66,514–15 (Dec. 26, 2018) (“Bump Stock Rule” or “Rule“). Under the Rule, “bump-stock-type devices are ‘machineguns’ as defined by the National Firearms Act and Gun Control Act because such devices allow a shooter of a semiautomatic firearm to initiate a continuous firing cycle with a single pull of the trigger.” Id. at 66,515. These devices, whether operated by an internal spring or manual pressure, “convert an otherwise semiautomatic firearm into a machinegun.” Id.
The Rule defined “single function of the trigger” as a “‘single pull of the trigger’ and analogous motions” and “automatically” as “the result of a self-acting or self-regulating mechanism that allows the firing of multiple rounds through a single pull of the trigger.” Id. Individuals currently in possession of bump stocks were directed to either destroy them
B.
In December 2018, pursuant to the Bureau‘s notice of final rulemaking, Plaintiffs sought a preliminary injunction to prevent the rule from taking effect. The District Court denied that request, finding the Bureau‘s interpretation of the relevant statutory terms—“single function of the trigger” and “automatically“—reasonable under Chevron. Guedes v. ATF, 356 F. Supp. 3d 109 (D.D.C. 2019) (”Guedes I“).
We affirmed the District Court‘s decision on the same basis. Guedes v. ATF, 920 F.3d 1, 6 (D.C. Cir. 2019) (per curiam) (”Guedes II“). In our view, the Chevron framework applied, notwithstanding Plaintiffs’ objections, because the rule was legislative in character; the government could not waive Chevron deference; and Chevron applies in equal force to provisions with criminal penalties. Id. at 17–28. Because we found “single function of the trigger” and “automatically” ambiguous under the National Firearms Act and Gun Control Act and the agency‘s interpretations reasonable, we ruled in the Bureau‘s favor.
The Supreme Court denied Plaintiffs’ petition for certiorari. Guedes v. ATF, 140 S. Ct. 789 (2020) (Mem.). In a separate statement, Justice Gorsuch articulated his view that Chevron did not apply because of the government‘s express waiver of the doctrine and the statute‘s criminal penalties. Id. at 790. He nevertheless concurred in the petition‘s denial, finding that the government‘s position could be substantiated at the merits stage and noting that other courts of appeals were currently considering challenges to the Rule. Id. at 791.
II.
We have jurisdiction over this appeal under
III.
A.
The government urges us to decide this appeal based on the law of the case doctrine, which instructs that “the same issue presented a second time in the same case in the same court should lead to the same result.” LaShawn A. v. Barry, 87 F.3d 1389, 1393 (D.C. Cir. 1996). The doctrine is a discretionary prudential doctrine, not a jurisdictional bar, and we decline to apply it here. Crocker v. Piedmont Aviation, Inc., 49 F.3d 735, 739–40 (D.C. Cir. 1995). This is not a situation in which we are reaching a different result on the same legal issue in the same case, which could require showing “extraordinary circumstances.” Sherley v. Sebelius, 689 F.3d 776, 781 (D.C. Cir. 2012) (quoting LaShawn A., 87 F.3d at 1393). Rather, we ultimately reach the ”same result” as the Guedes II panel, id., in that we likewise sustain the Bump Stock Rule.
B.
The threshold question is whether to treat this case as a matter of pure statutory interpretation or to apply the Chevron framework. Both parties advocate for the former. Plaintiffs argue that Chevron does not apply for a multitude of reasons: the rule is interpretive in nature; the government waived Chevron deference; the Court may not apply Chevron to a statute with criminal penalties; and the rule of lenity must supersede Chevron in the criminal context. The Bureau also characterizes the Rule as interpretive, and it likewise urges us to analyze the Rule under a statutory interpretation framework.
The Guedes II panel employed the Chevron framework—just as the District Court had done—in denying the motion for preliminary injunction. The panel concluded that the Bump Stock Rule was a legislative rule; the Bureau explicitly relied on Chevron in crafting it; the government cannot recharacterize a rule as legislative or interpretative during litigation; and the government cannot waive Chevron. 920 F.3d at 18, 21–23.
This approach also comports with how the Bureau engaged in the rulemaking exercise. The Bureau repeatedly described what it was doing as seeking to arrive at the “best interpretation” of the statutory text, and it relied principally on that reasoning during the rulemaking. Bump Stock Rule, 83 Fed. Reg. at 66,514, 66,517, 66,518, 66,521. This is also the Bureau‘s principal position on appeal. Appellee Br. 28. While the Bureau contended that it would reach the same result using a Chevron framework, that argument served as its fallback position. 83 Fed. Reg. at 66,527 (explaining that “this rule‘s interpretations of ‘automatically’ and ‘single function of the trigger’ in the statutory definition of ‘machinegun’ accord with the plain meaning of those terms,” but that “even if those terms are ambiguous, this rule rests on a reasonable construction of them“). This jurisprudential approach thus allows us to address the issues as the parties have principally framed them for resolution. If we are able to uphold the Bureau‘s definition based on its primary line of argument, there is no reason to reach its secondary one. See HollyFrontier Cheyenne Ref., LLC v. Renewable Fuels Ass‘n, 141 S. Ct. 2172, 2180 (2021) (declining to consider whether Chevron deference was due where government did not invoke it).
So too here, in relying on the ordinary tools of statutory interpretation—“text, structure, purpose, and legislative history,” see Pharm. Rsch. & Mfrs. of Am. v. Thompson, 251 F.3d 219, 224 (D.C. Cir. 2001)—we find that the Bureau has provided the best reading of the statute and that the statutory definition of machine gun as articulated in
Recall the National Firearms Act and Gun Control Act‘s definition of “machinegun“:
any weapon which shoots, is designed to shoot, or can be readily restored to shoot, automatically more than one shot, without manual reloading, by a single function of the trigger. The term shall also include the frame or receiver of any such weapon, any part designed and intended solely and exclusively, or combination of parts designed and intended, for use in converting a weapon into a machinegun, and any combination of parts from which a machinegun can be assembled if such parts are in the possession or under the control of a person.
Starting with “single function of the trigger,” the Bureau interprets it as a “‘single pull of the trigger’ and analogous motions.” Bump Stock Rule, 83 Fed. Reg. at 66,515. The phrase “analogous motions” includes “other methods of initiating an automatic firing sequence that do not require a pull,” like a push of a button or voice command. 83 Fed. Reg. at 66,515, 66,534–35. The Bureau‘s interpretation of “single function of the trigger” thus both defines a “function” of the trigger as a “pull” of the trigger and clarifies that a “pull” of the trigger is a shooter‘s volitional action that initiates an automatic firing sequence.
The Bureau offers the best reading of the statutory phrase in light of the plain language and purpose of the statute,
Such an interpretation is also consonant with the ordinary meaning of “function” at the time of the statute‘s enactment. Asgrow Seed Co. v. Winterboer, 513 U.S. 179, 187 (1995) (“When terms used in a statute are undefined, we give them their ordinary meaning.“).3 In 1934, “function” was defined as
Indeed, as early as Congress began discussing restrictions on machine guns through the National Firearms Act, a “single function of the trigger” was understood to mean a “single pull.” Congress initially proposed a definition of “machine gun” based on a weapon‘s capability to fire multiple shots, specifically a firearm that could automatically or semiautomatically shoot “twelve or more shots without reloading.” See National Firearms Act: Hearings Before the Comm. on Ways and Means, H.R., on H.R. 9066, 73d Cong. 1 (1934). Testifying before Congress, President of the National Rifle Association Karl T. Frederick advocated for an alternative definition that omitted the number of shots required and incorporated the “single function of the trigger” language. Id. at 40. Mr. Frederick further explained that “[t]he distinguishing feature of a machine gun is that by a single pull of the trigger the gun continues to fire as long as there is any ammunition in the belt or in the magazine.” Id.4 Roughly one
This definition also aligns with Congress‘s purpose in enacting federal legislation on machine guns to “[s]trictly regulate the manufacture, sale, transfer and possession of destructive devices” and to “combat the spiralling increase in serious crime in the United States.” S. Rep. No. 90-1097, at 2,290 (1968); see also Huddleston v. United States, 415 U.S. 814, 824 (1974) (“principal purpose” of the Gun Control Act was to reduce crime) (quoting id. at 2,113–14). Congress‘s concern for the danger posed by machine guns centered on their destructive potential and exacerbation of serious crime. Bump stocks present a heightened capacity for lethality as well; they are estimated to fire between 400 and 800 bullets per minute, as compared to a semiautomatic weapon‘s 180 bullets per minute. Amicus Br. for Appellee at 19–20. It is therefore consistent with congressional purpose to define “single function” with a focus on the weapon‘s ease of use.
Turning to “automatically,” the statutory text similarly favors the Bureau‘s definition. The Bureau defines “automatically” as “the result of a self-acting or self-regulating mechanism that allows the firings of multiple rounds.” Bump Stock Rule, 83 Fed. Reg. at 66,554. This definition pulls
The Bureau‘s prior interpretation of “automatically” focused more on the “self-acting” portion of the definition. 83 Fed. Reg. at 66,517–18. It previously concluded that a device must contain a spring or similar self-acting mechanism in order to operate “automatically“—therefore, bump stocks did not operate “automatically” because they required some manual input. Id. In the current rulemaking, the Bureau correctly recognized not only that “self-acting” can admit of some human input, but also that the word “automatically” encompasses devices that are “self-regulating.” Id. at 66,519.
This definition has found approval in past judicial interpretations. In United States v. Olofson, the Seventh Circuit concluded that under the National Firearms Act, “the adverb ‘automatically’ . . . delineates how the discharge of multiple rounds from a weapon occurs: as the result of a self-acting mechanism. That mechanism is one that is set in motion by a single function of the trigger and is accomplished without manual reloading.” 563 F.3d 652, 658 (7th Cir. 2009).
Statutory context also helps guide our interpretation here, given that “automatic” cannot be read in isolation. The statute defines a machine gun as a weapon that shoots “automatically more than one shot, without manual reloading, by a single function of the trigger.”
Rather than limiting the term “automatically,” the phrase “by a single function” clarifies it. With the use of “by,” “single function” is best understood as the antecedent to “automatically“—the initiating human action that sets off a self-regulating sequence of events. See United States v. Evans, 978 F.2d 1112, 1113 n.2 (9th Cir. 1992) (“‘by a single function of the trigger’ describes the action that enables the weapon to ‘shoot . . . automatically . . . without manual reloading,’ not the trigger mechanism.“). The statute does not suggest that human involvement is confined to the “predetermined point” of the operation. Instead, “rather than reading the phrase ‘by a single function of the trigger’ to mean ‘by only a single function of the trigger,’ the phrase can naturally be read to establish only the preconditions for setting off the ‘automatic’ mechanism, without foreclosing some further degree of manual input.” Guedes II, 920 F.3d at 31.
In sum, under the National Firearms Act and Gun Control Act, a “single function” of the trigger is best understood as a “single pull of the trigger” and “analogous motions,” while automatically is best understood to mean a “result of a self-acting or self-regulating mechanism.” 83 Fed. Reg. at 66,514. Taken together, these interpretations provide the best definition of a machine gun.
The best definition of machine gun settled, we turn to whether a bump stock fits within it. In terms of how a bump stock operates, the District Court found as follows: “A bump stock replaces a semiautomatic rifle‘s standard stock—the part of the rifle that rests against the shooter‘s shoulder—and enables the shooter to achieve a faster firing rate. To use a bump stock, the shooter must maintain forward pressure on the barrel and, at the same time, pull the trigger and maintain rearward pressure on the trigger. Once the shooter pulls the trigger, a bump stock harnesses and directs the firearm‘s recoil energy, thereby forcing the firearm to shift back and forth, each time ‘bumping’ the shooter‘s stationary trigger finger. In this way, the shooter is able to reengage the trigger without additional pulls of the trigger.” Guedes III, 520 F. Supp. 3d at 58, J.A. 43–44. Plaintiffs conceded that they were not challenging any of the District Court‘s factual findings. See Appellants’ Opening Br. 20 (“there is no confusion or dispute whatsoever regarding how a bump stock physically works“); Oral Arg. Tr. at 83–84 (answering “no” to the question of whether Appellants contended that the “District Court erroneously found a fact to be undisputed that was actually disputed“). Based on these facts, a bump stock is a machine gun under the best interpretation of the statute.
It bears noting that these factual findings correspond with the Bureau‘s statement of undisputed facts submitted in support of a motion for summary judgment, which cited evidence in the record in support of each statement. See Dkt. 61-3 ¶¶ 70–73 (“[u]sing a bump stock as designed and intended, a shooter does not need to pull the trigger more than once to produce more than one shot“). Plaintiffs did not properly dispute these facts, because their opposition failed to cite any evidence, as required by the federal and local rules. See Dkt. 63-1 ¶¶ 70–
Analyzing the District Court‘s factual findings under the Bump Stock Rule, we conclude that they are consistent with the best interpretation of the statute. First, as the District Court explained, a shooter operates a bump stock by a single pull, eliminating the need for additional pulls. Guedes III, 520 F. Supp. 3d at 58, J.A. 44. The shooter pulls the trigger once and his finger rests against the extension ledge, or the edge of the bump stock device. See J.A. 35.6 After the first pull of the trigger, the stock moves repeatedly back-and-forth, causing the trigger to “bump” against the stationary finger. Thus, only a single “function” or “pull” of the trigger by the shooter activates the multiple-shot sequence; no further pulls are needed. Put differently, using a bump stock, a single pull of the trigger propels the trigger against the stationary finger and
Second, a bump stock functions automatically because it is self-regulating. The bump stock “harnesses and directs the firearm‘s recoil energy” along a linear path, “thereby forcing the firearm to shift back and forth.” Guedes III, 520 F. Supp. 3d at 58, J.A. 43–44. That process will not conclude until the shooter releases forward pressure on the barrel, the weapon runs out of ammunition, or it malfunctions. In other words, a bump stock regulates the weapon‘s back-and-forth movement after a predetermined point in an operation—the shooter‘s pull of the trigger—and remains self-regulating as long as the shooter maintains pressure on the barrel.
Looking to the specific bump stock devices at issue, even the manufacturer‘s description admits of this interpretation of “automatic.” Plaintiff Damien Guedes purchased his bump stock device from Bump Fire Systems, while Plaintiff Shane Roden purchased a Slide Fire bump stock device. See Am. Compl. at 19–20, Guedes I (No.18-cv-02988). In an explanation of firing with a bump stock, the manufacturer Bump Fire Systems described it as a legal method of “full-auto firing.” Administrative Record 840. According to the description, the shooter operates the bump stock “by gripping the fore-end of the barrel and pulling it forward,” allowing him “to recreate the feeling of automatic firing.” Id. This description confirms what the Bureau sets forth: a bump stock enables a shooter to engage in automatic firing by pulling the trigger and maintaining pressure on the stock.
Accordingly, under the best interpretation of the statute, a bump stock is a self-regulating mechanism that allows a shooter to shoot more than one shot through a single pull of the trigger. As such, it is a machine gun under the National Firearms Act and Gun Control Act.
(iii)
Unlike the Bureau, Plaintiffs have failed to show that their “machine gun” definition is workable. See United States v. California, 381 U.S. 139, 165 (1965) (“we best fill our responsibility of giving content to the words which Congress employed by adopting the best and most workable definitions available“). With regard to “single function of the trigger,” Plaintiffs argue for a trigger-focused, rather than a shooter-focused, interpretation. In their view, the statutory language refers to the mechanical action of the trigger itself. See Appellants’ Opening Br. 23–24 (“‘function’ thus most reasonably refers to the mechanical action of the trigger” and “the function of the trigger is complete when the hammer is released, and a shot is fired“). Drawing upon the Sixth Circuit‘s now-overturned opinion, they contend that this phrase “necessarily refers to the trigger and not to the shooter or the shooter‘s act of pulling.” Appellants’ Opening Br. 23 (quoting Gun Owners of America, Inc. v. Garland, 992 F.3d 446, 471 (6th Cir. 2021), vacated, 19 F.4th 890 (6th Cir. 2021) (en banc)). Thus, “[a]ny subsequent bump, pull, or other interaction between the shooter‘s finger and the trigger . . . causes a second or subsequent function of the trigger, not a continuation of the initial completed function.” Id. at 24. Because a semiautomatic gun outfitted with a bump stock releases the hammer for each discharge, they assert that it does not fire more than one round via a single function of the trigger.
Yet, when asked at oral argument whether a hypothetical invention—a mechanical hand with a fast, continuously moving trigger finger that could be attached to a semiautomatic gun and operated by a push of a button—qualified as a machine gun, Plaintiffs answered in the affirmative. Oral Arg. Tr. at 81–83; see also id. at 56 for earlier discussion. According to Plaintiffs, we could redefine the trigger in this scenario to the button being pressed, rather than the internal trigger mechanism. But this reasoning diverges from Plaintiffs’ definition of “single function of the trigger” as a mechanistic act of the conventional firearm trigger itself. There are no two ways about it: either the trigger is the lever that releases the hammer and discharges a bullet, or it is not. J.A. 71. Such a concession shows that Plaintiffs’ definition is unworkable, internally inconsistent, and counterintuitive.
By contrast, the Bump Stock Rule‘s definition would encompass this mechanical hand device. In response to comments about different trigger activation methods, the Bureau added the phrase “and analogous motions” to the final rule, thereby including devices that function via “a push or other method of initiating the firing cycle.” 83 Fed. Reg. at 66,534–35. In this scenario, pushing the button neatly qualifies as an “analogous motion.”
Under Plaintiffs’ strict understanding of the “single function of the trigger” to mean the mechanistic movement of the trigger itself, this weapon would evade classification as a machine gun even though the shooter‘s initial pull of the trigger causes an automatic series of trigger movements and a resulting automatic series of shots, without any further input by the shooter whatsoever. The weapon is similar to the Akins Accelerator, see 83 Fed. Reg. at 66,517, except that the hypothetical weapon involves an internal motor that causes the trigger to automatically move back and forth after the initial pull, as opposed to an internal spring that causes the barrel to automatically move back and forth into a stationary trigger finger after the initial pull: in either case, the trigger continues to move, and shots continue to fire, without any additional input from the shooter.
Plaintiffs believe that the Akins Accelerator was mistakenly dubbed a machine gun because it, like a bump stock
Plaintiffs’ interpretation of “automatically” is no less problematic. They interpret “automatically” as “self-acting” or requiring only “the expressly specified initiating action” before operating on its own. Appellants’ Opening Br. 27–28. In their view, bump stocks do not operate automatically because the shooter must maintain constant forward pressure on the bump stock with his non-trigger hand to continue firing. This definition would remove what Plaintiffs would describe as a prototypical machine gun from the realm of “automatic,” as the shooter must both pull the trigger and keep his finger depressed on the trigger to continue firing. Once the force is removed from the trigger, firing ceases. Per Plaintiffs’ definition, only a gun that required no human input to fire more than a single shot would qualify as a machine gun. By this logic, we would no longer characterize even the prototypical machine gun as a “machine gun,” given the extent of rearward pressure on the trigger required to operate it. That cannot be right.
Finally, Plaintiffs’ fear that all semiautomatic weapons will be subject to regulation because they can be modified with everyday items, like belt loops, to fire automatically is unfounded. Unlike a bump stock, a rubber band or belt loop is not automatic because it is not self-regulating. Rather than harnessing the firearm‘s recoil energy from a rubber band or belt loop in a linear path to engage in a continuous firing sequence, the shooter must harness and direct the recoil energy himself. Bump Stock Rule, 83 Fed. Reg. at 66,533. As the Bureau explained, “the belt loop or similar manual method requires the shooter to control the distance that the firearm recoils and the movement along the plane on which the firearm recoils.” Id. Harnessing the recoil energy without an automatic device requires a great deal of skill and renders it exponentially more difficult to bump fire. These everyday devices are “objectively different” from bump stocks and do not qualify as machine guns under the Bureau‘s interpretation. Id.
Plaintiffs also urge us to apply the rule of lenity. The rule of lenity instructs courts to resolve ambiguity in favor of a criminal defendant, but it “only applies if, after considering text, structure, history, and purpose, there remains a grievous ambiguity or uncertainty in the statute that the Court must simply guess at what Congress intended.” Maracich v. Spears, 570 U.S. 48, 76 (2013). See also Staples, 511 U.S. at 619 n.17 (applying rule of lenity was unnecessary where meaning could be derived through interpretive tools).
It is only where the Court has exhausted “everything from which aid can be derived” that lenity plays a role. Muscarello v. United States, 524 U.S. 125, 138 (1998) (internal quotation marks and citations omitted). For example, in United States v. Bass, the Court applied the rule of lenity where it could not decisively interpret the prosecution‘s evidentiary burden from Title VII of the Omnibus Crime Control and Safe Streets Act of 1968. 404 U.S. 336, 337–38, 347. Given the lack of clear statutory language, legislative history, and a clear statement of congressional purpose, the Court resorted to lenity to approve a narrower construction in this instance. Id. at 347–50. See also United States v. Universal C.I.T. Credit Corp., 344 U.S. 218, 221 (1952) (turning to lenity in Fair Labor Standards Act case where “literal reading” of text did not illuminate statutory construction). Fortunately, we are not left to “guess at” the meaning of the text at issue here, see Maracich, 570 U.S. at 76, given the array of tools at our disposal, including the statute‘s plain language, prior case law, contemporaneous understandings, and congressional purpose. As a result, we are not left with the type of “grievous ambiguity,” see id., that would require the rule of lenity‘s application here.
The manufacturer of one of the bump stock devices owned by Plaintiffs once promoted that its product enabled “Spraying 900 rounds in 60 seconds.” What is Bump Fire, Bump Fire Sys., https://bit.ly/3PdRTNH. We join those circuits in concluding that these devices, which enable such prodigious rapid-fire capability upon a pull of the trigger, fall within the definition of “machine gun” in the National Firearms Act and Gun Control Act. For the foregoing reasons, the District Court‘s judgment is affirmed.
Figure 1: The shooter pushes the firing unit so that it slides forward inside the bump stock and he pulls the trigger.
Figure 2: After the first shot, the shooter‘s finger rests against the extension ledge of the bump stock, which “constrains” the recoil and the opposing forward force so that the firing unit slides in a linear direction, propelling the firing unit against the stationary finger, causing the firing cycle to repeat.