AICS Magazine
Accuracy International Chassis Magazine (AICS) is a detachable style magazine. Accuracy International Magazine. Accuracy International Chassis System.
The "AICS-style" short action box magazine was originally manufactured for the Accuracy International Chassis System, but can now be found on several production rifles, such as the SIG Sauer CROSS, the Ruger Gunsite Scout, Ruger Precision Rifle, some Ruger American Rifle models and some new production models by Remington (Model 700 PCR, 700 Tactical Chassis, 700 Magpul, and 700 Magpul Enhanced). AICS-style magazines can also be found on many custom rifles, and aftermarket conversion kits (known as "bottom metals") are available for several different rifle models and are made by several different manufacturers.
In addition to Accuracy International, there are now aftermarket manufacturers offering AICS-style magazines, such as Magpul, Accu-Mag and Modular Driven Technologies (MDT). Examples of other magazine designs include the STANAG magazine (for 5.56×45mm NATO length cartridges) and SR-25 pattern magazine (for 7.62×51mm NATO length cartridges).
AICS magazines are pretty much the standard for bolt action rifles that use a detachable magazine. The Ruger Precision and Scout Rifles use them, people convert their Tikkas to AICS instead of CTR mags when they install a chassis, and countless 700, Savage, and Howa builds use them too. Ruger just recently revealed models of their American Rifles that use AICS magazines or AR-15 magazines (depending on caliber).
The AICS mags are the most common in bolt action rifles because their design works with more of them. They are narrow and single-stack. The AICS pattern short action magazine is essentially now the standard magazine for most bolt action rifles. A big plus of these bolt action mags is that they have the ability to allow for handloaded ammo with longer-than-normal overall length and can easily feed wildcat cartridges and neck-sized brass.
The AICS Magazine is made for bolt-action rifles meaning they will not fit AR-platform rifles.