Rifle Parts

AR-15 Parts and Components

The AR-15 is the most modular rifle platform available, with a massive aftermarket ecosystem for every component. The most common upgrades are triggers, handguards, stocks, and muzzle devices. A drop-in trigger group from Geissele or Timney dramatically improves accuracy potential over the mil-spec trigger. Free-float handguards from Aero Precision, Daniel Defense, or BCM improve accuracy by eliminating barrel contact and provide more real estate for lights, lasers, and grips. Collapsible stocks from Magpul, B5 Systems, and Luth-AR allow length-of-pull adjustment. Any AR-15 upgrade starts with knowing whether your rifle is mil-spec or proprietary — most are mil-spec, which means the vast majority of aftermarket parts will fit.

Triggers

The trigger is the single upgrade with the greatest impact on accuracy and shooting performance. A mil-spec AR trigger typically breaks at 6–8 lbs with significant creep and reset. A quality aftermarket trigger reduces pull weight to 3.5–4.5 lbs with a cleaner break and shorter reset. Geissele’s SSA-E is the standard for duty and precision use. Timney makes excellent drop-in units for both AR-15 and bolt-action rifles including Remington 700, Winchester Model 70, and Savage. For bolt-action precision rifles, a Timney or Jewell trigger is often the first and most impactful upgrade a shooter can make.

Barrels

Barrel quality directly determines accuracy potential. Cold hammer-forged and button-rifled barrels both produce accurate results when made to tight tolerances. For AR-15 barrels, chrome-lined bores offer the best durability and corrosion resistance for hard use and high round counts. Stainless steel barrels offer slightly better inherent accuracy at the cost of corrosion resistance. Barrel length affects velocity and handling: 16″ is the minimum for a non-NFA rifle, 18″ provides a good balance of velocity and maneuverability, and 20″ maximizes velocity for longer-range shooting. Twist rate must match your intended bullet weight — 1:8 is the most versatile for 5.56, handling everything from 55gr to 77gr projectiles.

Stocks and Handguards

Stocks affect fit, recoil management, and cheek weld. Magpul’s MOE and CTR stocks are the most popular aftermarket options for AR-15s, offering improved cheek weld and storage compartments over mil-spec stocks. Fixed stocks like the Magpul PRS are popular for precision builds. For bolt-action rifles, chassis systems from MDT, Masterpiece Arms, and Oryx replace the factory stock with an aluminum chassis that provides better ergonomics and a more stable platform for precision shooting. Handguards for AR-15s determine your mounting options for accessories and whether the barrel floats freely. M-LOK and Picatinny rail handguards are the current standard.

Muzzle Devices

Muzzle devices thread onto the barrel and serve several functions. Flash hiders (A2 birdcage style) reduce visible muzzle flash, which matters for night shooting and not giving away your position. Compensators redirect gas upward to reduce muzzle rise between shots. Muzzle brakes redirect gas sideways or rearward to reduce felt recoil — very effective but significantly louder. Suppressors thread onto compatible muzzle devices or directly onto the barrel and require an NFA tax stamp. Match your muzzle device thread pitch to your barrel: 1/2x28 is standard for 5.56/.223, 5/8x24 is standard for .308.

Related Pages

Browse all gun parts and accessories, including AR-15 specific parts. See our triggers and barrels pages for dedicated selection. Shop AR-15 rifles and bolt-action rifles if you’re looking for a complete firearm.