The A1 upper receiver is lighter, so that might suit your physical needs better if you are a smaller person, unlike the heavier A2 model. In addition to these differences, you may ask yourself what the benefit of each rifle is. The A4 model is the most common model on the market today. Some models come with a high rise configuration which provides a higher scope positioning.įinally, the A4 upper receiver is very similar to the A3 upper receiver except that it includes M4 style feed ramps which complement the feed ramps found on the M4 barrel. It also includes forward assists and rifle cuts in the feed ramp. Many A3 models feature a Picatinny or Weaver rail to serve as a mounting platform for scopes or other accessories. The A3 receiver can be distinguished from the other models by its flat top configuration, featuring a detachable carrying handle. The A2 has a twist rate of either 1:7 or 1:9. The A2 barrel is also heavier, and features left-handed brass and rounded handguards, in contrast to the triangular handguards of the A1 model. Unlike the A1 model, though, the A2 model is adjustable for elevation up to six hundred yards, as well as for the effect of wind in deflecting a bullet, otherwise known as windage. Like the AI model, it is equipped with a fixed carry handle and a forward assist. The A2 receiver is an upgraded version of the A1 which was introduced in the eighties. The A1 receiver is accurate to within four-hundred-and-fifty yards. This model also includes a flip rear sight for elevation and is equipped with short and long-range apertures. A1 upper receivers feature a light profile barrel, forward assists, and a fixed carry handle. The A1 upper receiver is the original and was developed for use by soldiers in the Vietnam War. These receivers are named in the same way the military designated their M-4 assault rifles. The four main receivers are known as the A1, A2, A3 and A4 upper receiver, respectively. There are four types of AR-15 upper receiver, each with its own distinct design, advantages or disadvantages. Every essential component of an AR-15 is contained in the upper receiver. An upper receiver is the upper half of a rifle.

Barreled a2 carry handle upper