A device designed to modify a specific firearm’s magazine well, allowing it to accept different ammunition cartridges or magazines is typically referred to as a magazine conversion. For example, such a device might allow a rifle originally chambered for .308 Winchester to accept .223 Remington ammunition using a different magazine. This often involves changes to the bolt, barrel, or other components, in addition to the magazine itself.
These adaptations can offer significant advantages to firearm owners, such as increased versatility, reduced ammunition costs, or access to cartridges better suited for specific purposes. Historically, conversions have played a role in extending the lifespan of firearms platforms, allowing them to remain relevant despite changing ammunition availability or evolving tactical requirements. Furthermore, they can provide an affordable alternative to purchasing a completely new firearm.