Plenty of folks build 16 inch carbines, and plenty more build ARPs, but there is a dedicated subset of those that build true, full-size rifles.

For these, it’s hard to beat a 20 inch AR upper, if only for the number of benefits that a 20 inch upper can confer. 

Let’s start with these 5, which are arguably the most important. 

• A flatter trajectory: Because the longer barrel traps gasses behind the bullet for longer, it enables the bullet to accelerate for longer before it clears the bore. This, in turn, results in a higher muzzle velocity (more on that in a second). For our purposes here, the main effect is that a longer barrel results in a flatter trajectory and less bullet drop, if you hold all else equal. This can make a rifle with a longer barrel better for long-range shooting. 
• More power: For the same reason mentioned above, a rifle with a longer barrel will result in a bullet that leaves the muzzle at a higher velocity than that same cartridge and load from a shorter barrel. This results in higher FPS at the muzzle and more muzzle energy as well. 
• More stability: The longer the rifle barrel, the heavier the rifle will be, and with a 20 inch rifle barrel, you can expect much more stability from the platform. This will make it harder to carry and shoot the rifle for longer, but at the same time, it will result in a platform that offers much greater stability for disciplines like hunting or long-range shooting. 
• A more forgiving sight radius: Just in case you’re not familiar, sight radius refers to the distance between the front and rear sight. To shoot accurately over irons, you need to align them perfectly; a misalignment between them will result in a bore that is pointed in a direction other than the apparent point of aim. The problem with short barrels is that the shorter distance between the front and rear sights magnifies this issue and can make it more difficult to shoot a rifle with iron sights more accurately. This problem abates somewhat as the length of the barrel increases, which in turn increases the sight radius. The rifle itself won’t be more accurate (after all, a longer barrel can result in complicated barrel harmonics) but at the same time, the longer sight radius makes it easier to shoot the rifle more accurately. 
• Lower recoil, all else being equal: The barrel is one of the heaviest components of an AR style rifle. As a result, a longer barrel will result in a much heavier platform. That extra static mass will result in a heavier rifle that more easily absorbs recoil. 

Start Your Build with a 20 Inch AR Upper from MCS Gearup 

Not sure where to start with parts for an AR style rifle with a 20 inch barrel? You can get everything you need online at MCS Gearup. 

In addition to 20 inch AR uppers (and other assembled uppers in a wide variety of sizes and configurations for ARPs and SBRs) they carry AR build kits and other piecemeal parts. 

Whatever your plan is for your next build, get what you need to start online at MCS Gearup and don’t be shy about reaching out to them at Sales@MCSGearup.com if you have any questions.

For more information about Buffer Tube Kits and Micro Conversion Kits Please visit: MCS Gearup.