AR Platform Caliber Compatibility List


Just some useful information on what Calibers work with each platform.


Centerfire calibers inch measurement

.17 Remington
.204 Ruger
.223 Remington - .223 cartridges may function in a 5.56×45mm rifle, however 5.56×45mm cartridges will produce excessive pressure in a .223 rifle.
.223 Remington Ackley Improved
.243 Winchester Super Short Magnum
.25 Winchester Super Short Magnum
.25-45 Sharps
.277 Wolverine (6.8×39mm)
.30 Carbine
.30 Herrett (.308-6.8)
.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

5.56x45mm NATO
6mm-223 Remington
6mm Fat Rat (6mm Grendel AI)
6mm AR Turbo
6mm BRX
5.7×28mm FN
6.5mm BRX
6.5mm Grendel
6.5mm Patriot Combat Cartridge
6.8×39mm (.277 Wolverine)
6.8mm Remington SPC
7.62×37mm Musang
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
.408 CheyTac
.338 Lapua Magnum
.300 Winchester Magnum


Center fire caliber

Original caliber: 7.62×51mm NATO

.243 Winchester
.260 Remington
6.5mm Creedmoor
6mm Creedmoor
6×47mm Lapua
6.5×47mm Lapua
7mm-08 Remington
.308 Winchester - considered interchangeable with 7.62×51mm NATO according to SAAMI.
.338 Federal
.358 Winchester
.45 Raptor


@Nicky, thanks for this.


My 3rd build will use the AR10 platform so I did a lot of research on what caliber I wanted to do… Decided on the 45 Raptor. It’ll be sweet but going to take my sweet ass time with it.


Thanks for posting this list.

Maybe it could be anchored at the top.

archived #5