When it comes to building an AR-15, there are loads of options in the market for parts. There are several companies that make high-quality parts for AR-pattern rifles, and Olympic Arms AR 15 Upper Receiver is one of the best.
Generally, AR-15s are chambered in 5.56 Nato, which is perhaps the most popular rifle caliber in the US, however, 5.45×39 is also a very capable caliber, with very similar ballistics to 5.56×45 Nato. in fact, 5.45 is a more accurate caliber, because of its lower length to width ratio. 5.45 is used by the Russian military, and is a very popular caliber in many countries and the US as well.
If you are looking for a super reliable and affordable AR-15 upper, you have to check out the Olympic Arms AR-15 Upper. This A2 style upper assembly is chambered in 5.45x39mm, which is a very common caliber used in the AK-74.
Olympic Arms Design
The design of this upper assembly is inspired by a classic military spec M4, it has an A2 style upper carry handle, front and rear sights, and flash hider. The Olympic Arms AR-15 Upper upper assembly also includes a reliable upper receiver, high-end barrel, gas system, bolt carrier group, and charging handle.
The barrel is 16 inches long. It is made from high-quality stainless steel. It has a matte black finish to go with the Aesthetic of the rifle. The barrel has 1:8 twist rifling, and 1/2″-28 thread pitch. This allows a wide range of muzzle devices to be mounted onto this upper. However, it comes with a simple A2 style, birdcage flash hider.
Olympic Arms AR 15 Upper Receiver – Handguard
Moving on to the handguard. This upper assembly has a simple polymer handguard. Like classic M4 mil Spec rifles, it doesn’t have any M-Lok or Picatinny rails on it. However, it does offer a very comfortable grip. This upper assembly comes with a combo front sight gas block. With a carbine length gas tube, which works great with the 16-inch barrel. It allows enough gas into the chamber for reliable operation. But not too much that it creates an overpowered recoil impulse.
Olympic Arms AR 15 Upper Receiver – Sights
The rear sight is integrated into the carry handle, like A2-style AR rifles. It is adjustable for windage and elevation. The receiver has a forward assist and port door. As well and comes with a high-quality bolt carrier group and a standard mil-spec charging handle as well. It is compatible with any AR-15 lower, and also comes with a 30-round magazine.
If you are looking for complete AR-15 rifles, built on an Olympic arms upper, you can look for some options here.
Overall, if you are looking to build an AR-pattern rifle chambered in 5.45x39mm, then the Olympic Arms AR-15 upper is a really good option. It is reliable, affordable, and has a classic mil-spec aesthetic as well.