Document ID: ./input/supremecourt_opinions/opinions/23pdf/22-976_e29g.pdf
Page Number: 19.0

Cite as:  602 U. S. ____ (2024) 

15 

Opinion of the Court 

cause a weapon to fire “more than one shot”—a “single func-
tion of the trigger.”  If something more than a “single func-
tion  of  the  trigger”  is  required  to  fire  multiple  shots,  the 
weapon does not satisfy the statutory definition.  As Judge 
Henderson put it, the “statutory definition of ‘machinegun’ 
does not include a firearm that shoots more than one round 
‘automatically’ by a single pull of the trigger AND THEN 
SOME.”   Guedes  v.  Bureau of  Alcohol,  Tobacco,  Firearms 
and Explosives, 920 F. 3d 1, 44 (CADC 2019) (opinion con-
curring in part and dissenting in part). 
  Firing multiple shots using a semiautomatic rifle with a 
bump stock requires more than a single function of the trig-
ger.   A shooter must  also  actively maintain  just the right 
amount of forward pressure on the rifle’s front grip with his 
nontrigger  hand.    See  supra,  at  2–3.    Too  much  forward 
pressure and the rifle will not slide back far enough to re-
lease and reset the trigger, preventing the rifle from firing 
another  shot.    Too  little  pressure  and  the  trigger  will  not 
bump the shooter’s trigger finger with sufficient force to fire 
another shot.  Without this ongoing manual input, a semi-
automatic  rifle  with  a  bump  stock  will  not  fire  multiple 
shots.    Thus,  firing  multiple  shots  requires  engaging  the 
trigger one time—and then some.7 
  ATF and the dissent counter that machineguns also re-
quire  continuous  manual  input  from  a  shooter:  He  must 

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7

 The  dissent  seemingly  concedes  this  point,  repeatedly  recognizing 
that the shooter must both pull the trigger and maintain forward pres-
sure on the front grip.  See, e.g., post, at 6 (“[A] single pull of the trigger 
provides continuous fire as long as the shooter maintains forward pres-
sure on the gun”); ibid. (“A bump-stock-equipped semiautomatic rifle is 
a machinegun because . . . a shooter can . . . fire continuous shots without 
any  human  input  beyond  maintaining  forward  pressure”);  post,  at  10 
(“[A] shooter of a bump-stock-equipped AR–15 need only pull the trigger 
and maintain forward pressure”); post, at 13 (“After a shooter pulls the 
trigger,  if  he  maintains  continuous  forward  pressure  on  the  gun,  the 
bump stock harnesses the recoil to move the curved lever back and forth 
against his finger”).