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Page Number: 12.0

8 

GARLAND v. CARGILL 

Opinion of the Court 

ger  a  single  time  will  cause  the  firing  mechanism  to  dis-
charge only one shot.  To understand why, it is helpful to 
consider  the  mechanics  of  the  firing  cycle  for  a  semiauto-
matic rifle.  Because the statutory definition is keyed to a 
“function of the trigger,” only the trigger assembly is rele-
vant for our purposes.  Although trigger assemblies for sem-
iautomatic  rifles  vary,  the  basic  mechanics  are  generally 
the same.  The following series of illustrations depicts how 
the trigger assembly on an AR–15 style semiautomatic rifle 
works.3  In each illustration, the front of the rifle (i.e., the 
barrel) would be pointing to the left. 
  We begin with an overview of the relevant components: 

Figure 1. 

The trigger is a simple lever that moves backward and for-
ward.  P. Sweeney, Gunsmithing the AR–15, p. 131 (2016).  
The square point at the top left edge of the trigger locks into 
a  notch  at  the  bottom  of  the  hammer.    P.  Sweeney,  Gun-
smithing: Rifles 269 (1999).  The hammer is a spring-loaded 
part that swings forward toward the barrel and strikes the 
firing pin, causing a shot to fire.  Ibid.  The disconnector is 
the component responsible for resetting the hammer to its 
—————— 

3

 These illustrations are found in the Brief for FPC Action Foundation 

as Amicus Curiae 14–15.