Border Patrol agents are issued the H&K P2000 double action LEM (Law Enforcement Modification) pistol in .40 S&W caliber.
It can contain as many as 13 rounds of ammunition (12 in the magazine and 1 in the chamber).
Up until 1995 the Border Patrol issued its Patrol Agents a .357 Magnum revolver as their duty sidearm, a Smith & Wesson or Ruger model large frame, six shot revolver.
 The Border Patrol preferred this weapon because it did not jam in harsh conditions, like those of the southwestern border, and also because of the strong "stopping power" of the .357 Magnum cartridge.
Although up until 1995 Patrol Agents could purchase a weapon from the agency list of approved authorized personal weapons for duty carry.
This list included the Glock Models 17 and 19 pistols in 9mm, the SIG Sauer P220 pistol in .45 ACP caliber, the Colt Python .357 Magnum revolver, and the Smith & Wesson Model 19/66 .357 Magnum revolver.
The Border Patrol adopted the Beretta Model 96D, a .40 S&W caliber semi-automatic pistol (modified for Double-Action Only) (with 11-round capacity magazines) as its duty issue sidearm in 1995.
 The .40 S&W caliber jacketed hollow-point cartridge was adopted because of its excellent "stopping" power and its superior ballistic characteristics over the 9mm cartridge.
In late 2006 the H&K P2000 pistol was adopted as the Border Patrol's primary duty sidearm.
 The H&K Model USP Compact pistol, H&K Model P2000SK (sub-compact) and Beretta M96D .40 S&W caliber pistols are authorized as secondary sidearms.

On April 9, 2019, CBP announced that the U.S. Border Patrol would transition from the .40 caliber H&K P2000 to an unnamed 9-millimeter Glock pistol, by the end of fiscal year 2021.
 It has since been revealed that the three Glock handguns that would be issued to CBP officers and agents would be the model G26, model G19, and the specifically manufactured for CBP model G47.

Like many other law enforcement agencies, the 12 gauge Remington Model 870 is the standard pump-action shotgun.
The Border Patrol issue Model 870 has been modified by Scattergun Technologies to Border Patrol specifications including: a 14-inch barrel, a five-shot capacity magazine, a composite stock with pistol grip, and night sights with a tactical "ghost-ring" rear sight.
The old Border Patrol "anti-bandit" units used to use a 12-gauge, semi-automatic shotgun with a sawed-off barrel.
This weapon had the designated name of a "Sidewinder."
 The USBP anti-bandit units were decommissioned in the late 1980s.

Border Patrol agents also commonly carry the  Heckler & Koch HK53 variant HK33, .223 caliber Colt M4 Carbine (Specifically the updated M4A1) and the H&K UMP .40 caliber submachine gun.
The .308 caliber M14 rifle is used for ceremonial purposes and by agents who are qualified with the rifle and BORTAC.

As less than lethal options, the Border Patrol uses the FN 303 Launcher.
 The FN 303 fires plastic pellet balls containing OC (Oleoresin Capsicum) Pepper dust.
 The plastic pellet balls burst on impact spraying the suspect with OC Pepper dust and also act as an impact projectile.
The Border Patrol also issues its agents OC Pepper spray canisters, tasers and a collapsible/telescopic (or telescoping) steel police baton.
Border Patrol agents are issued the H&K P2000 double action LEM (Law Enforcement Modification) pistol in .40 S&W caliber. It can contain as many as 13 rounds of ammunition (12 in the magazine and 1 in the chamber). Up until 1995 the Border Patrol issued its Patrol Agents a .357 Magnum revolver as their duty sidearm, a Smith & Wesson or Ruger model large frame, six shot revolver.  The Border Patrol preferred this weapon because it did not jam in harsh conditions, like those of the southwestern border, and also because of the strong "stopping power" of the .357 Magnum cartridge. Although up until 1995 Patrol Agents could purchase a weapon from the agency list of approved authorized personal weapons for duty carry. This list included the Glock Models 17 and 19 pistols in 9mm, the SIG Sauer P220 pistol in .45 ACP caliber, the Colt Python .357 Magnum revolver, and the Smith & Wesson Model 19/66 .357 Magnum revolver. The Border Patrol adopted the Beretta Model 96D, a .40 S&W caliber semi-automatic pistol (modified for Double-Action Only) (with 11-round capacity magazines) as its duty issue sidearm in 1995.  The .40 S&W caliber jacketed hollow-point cartridge was adopted because of its excellent "stopping" power and its superior ballistic characteristics over the 9mm cartridge. In late 2006 the H&K P2000 pistol was adopted as the Border Patrol's primary duty sidearm.  The H&K Model USP Compact pistol, H&K Model P2000SK (sub-compact) and Beretta M96D .40 S&W caliber pistols are authorized as secondary sidearms.
On April 9, 2019, CBP announced that the U.S. Border Patrol would transition from the .40 caliber H&K P2000 to an unnamed 9-millimeter Glock pistol, by the end of fiscal year 2021.  It has since been revealed that the three Glock handguns that would be issued to CBP officers and agents would be the model G26, model G19, and the specifically manufactured for CBP model G47.
Like many other law enforcement agencies, the 12 gauge Remington Model 870 is the standard pump-action shotgun. The Border Patrol issue Model 870 has been modified by Scattergun Technologies to Border Patrol specifications including: a 14-inch barrel, a five-shot capacity magazine, a composite stock with pistol grip, and night sights with a tactical "ghost-ring" rear sight. The old Border Patrol "anti-bandit" units used to use a 12-gauge, semi-automatic shotgun with a sawed-off barrel. This weapon had the designated name of a "Sidewinder."  The USBP anti-bandit units were decommissioned in the late 1980s.
Border Patrol agents also commonly carry the  Heckler & Koch HK53 variant HK33, .223 caliber Colt M4 Carbine (Specifically the updated M4A1) and the H&K UMP .40 caliber submachine gun. The .308 caliber M14 rifle is used for ceremonial purposes and by agents who are qualified with the rifle and BORTAC.
As less than lethal options, the Border Patrol uses the FN 303 Launcher.  The FN 303 fires plastic pellet balls containing OC (Oleoresin Capsicum) Pepper dust.  The plastic pellet balls burst on impact spraying the suspect with OC Pepper dust and also act as an impact projectile. The Border Patrol also issues its agents OC Pepper spray canisters, tasers and a collapsible/telescopic (or telescoping) steel police baton.
United States Border Patrol