List of AR platform calibers

The AR platform has become widely popular for makers of military and sporting rifles. Although the designations "AR-10" and "AR-15" are trademarks of Colt's Manufacturing Company variants of both are made by many manufacturers.

AR-15 calibers

Original caliber: 5.56×45mm NATO

Rimfire calibers

• .17 HMR
• .17 Winchester Super Magnum
• .22 Long Rifle

Centerfire calibers inch measurement

• .17 Remington
• .204 Ruger
• .223 Remington - .223 cartridges may function in a 5.56x45mm rifle, however 5.56x45 cartridges will produce excessive pressure in a .223 rifle.
• .243 Winchester Super Short Magnum
• .25 Winchester Super Short Magnum
• .30 Carbine
• .30 Remington AR
• 300 AAC Blackout (7.62×35mm)
• .300 Whisper
• .375 Reaper
• .40 S&W
• .45 ACP
• .450 Bushmaster
• .458 SOCOM
• .50 Beowulf
• .50 Action Express

Centerfire calibers metric measurement

• 5.45x39mm
• 5.7x28 FN
• 6.5mm Grendel
• 6.8 mm Remington SPC
• 7.62×37mm Musang
• 7.62×39mm
• 7.62×40mm Wilson Tactical
• 9mm Parabellum
• 10mm Auto

Calibers which will not feed but which are used in rifles where the receiver functions only as a trigger group

• .50 BMG

AR-10 calibers

Original caliber: 7.62x51 mm NATO

Center fire calibers

• .243 Winchester
• .260 Remington
• 6.5mm Creedmoor
• 7mm-08 Remington
• .308 Winchester - considered interchangeable with 7.62x51 NATO according to SAAMI.
• .338 Federal
• .358 Winchester