The AR platform remains one of the most customizable firearm systems available today. Its modular design allows shooters to tailor everything from caliber to barrel length, creating a rifle or pistol that matches specific goals. Among the many options available, the 7.62x39 upper and the 5 inch ar pistol upper standout as two popular choices, each with their own advantages. 

Chambering an AR in 7.62x39 combines the classic characteristics of this cartridge with the familiar controls of the AR platform. Known for its heavier projectile and reliable terminal performance, the 7.62x39 round is well suited for a range of uses — from range shooting to hunting medium-sized game. This setup appeals to shooters who want something different from the standard 5.56 NATO build without moving away from the AR’s ergonomics. 

Ammunition availability is another strong point for this caliber. Because it has been widely used for decades, shooters have access to a steady supply of factory-loaded options at reasonable prices. This makes it a practical solution for those who value cost-effective shooting while still benefiting from the round’s proven effectiveness. 

On the compact side, the 5-inch AR pistol upper is ideal for shooters who need a short, highly maneuverable build. Its reduced length allows for quick handling in close-quarters environments, which can be useful for home defense or training in tight spaces. While a shorter barrel naturally limits muzzle velocity compared to a rifle-length option, many shooters appreciate the balance it strikes between portability and firepower. 

Compact uppers also work well with accessories. Optics, lights, and suppressors are commonly added to improve usability, while muzzle devices can help manage recoil and flash. These customizations further enhance the practical use of a small AR pistol build and allow owners to tailor it to their personal preferences. 

Together, these two configurations highlight just how versatile the AR system can be. The 7.62x39 upper delivers power and range with a proven cartridge, while the 5-inch pistol upper focuses on mobility and ease of handling. This ability to switch between very different setups using the same core platform is one of the reasons the AR remains a top choice for enthusiasts. 

Shooters interested in building or upgrading their AR can find a range of quality components and complete uppers from suppliers like Moriarti Armaments, making it easier to put together a configuration that fits their needs.