AR-15 Upper Parts: What You Should Know

The upper receiver of an AR-15 is a crucial component that houses the barrel, bolt carrier group (BCG), and other parts responsible for the firing mechanism. Understanding the upper parts is essential for building, customizing, and maintaining your AR-15. Here’s what you should know about AR-15 upper parts:

1. Upper Receiver:

  • The upper receiver is the top half of the AR-15 and houses several key components. It connects to the lower receiver and includes the ejection port, forward assist, and picatinny or M-Lok rail for accessory attachment.

2. Barrel:

  • The barrel determines the firearm’s caliber, length, and accuracy potential. AR15 Parts Kits barrels come in various lengths and profiles to suit different purposes, such as long-range shooting, close-quarters combat, or general use.

3. Muzzle Device:

  • The muzzle device is attached to the barrel’s muzzle and serves multiple functions. It can reduce recoil, control muzzle rise, and minimize flash. Common types include flash hiders, compensators, and muzzle brakes.

4. Gas Block:

  • The gas block regulates the flow of gas from the barrel into the gas tube. There are two main types: fixed and adjustable. Adjustable gas blocks allow for fine-tuning the rifle’s gas system, improving recoil management and reliability.

5. Gas Tube:

  • The gas tube connects the gas block to the upper receiver. It directs gas from the fired cartridge to cycle the BCG. Gas tubes come in various lengths to match barrel lengths and gas systems.

6. Handguard/Forend:

  • The handguard, also known as the forend, covers the barrel and gas system and provides attachment points for accessories like optics, lights, lasers, and grips. Handguards can be free-floating or drop-in, and they come in different lengths and attachment systems (e.g., M-Lok, KeyMod, Picatinny).

7. Bolt Carrier Group (BCG):

  • The BCG is responsible for chambering, firing, extracting, and ejecting rounds. It consists of several components, including the bolt, bolt carrier, cam pin, and firing pin.

8. Charging Handle:

  • The charging handle is used to manually chamber a round, clear malfunctions, and engage the bolt catch. It is located on the upper receiver’s rear and connects to the BCG.

9. Forward Assist:

  • The forward assist is a button located on the upper receiver that allows the shooter to manually force the bolt closed in case of a malfunction or to ensure proper chambering.

10. Dust Cover (Ejection Port Cover): – The dust cover is a hinged cover that protects the ejection port from debris and fouling. It flips open when the rifle is fired.

11. Ejection Port: – The ejection port is the opening through which spent casings are ejected after firing. It is typically located on the right side of the upper receiver.

12. Iron Sights and Optics: – The upper receiver provides a platform for mounting iron sights, scopes, red dot sights, and other optics. It’s crucial to choose the appropriate optic mount or riser for proper sight alignment.

Understanding these AR-15 upper parts is essential for customizing your rifle to suit your specific needs and preferences. When building or modifying your AR-15, it’s essential to follow safety guidelines, adhere to local firearm regulations, and consult the manufacturer’s instructions for each component. Proper maintenance and regular cleaning are also vital for the reliable and accurate performance of your AR-15 upper.