Here because you’re considering an AR pistol build? Don’t start the build without figuring out what size AR15 pistol upper you want. From the shortest 5 inch AR pistol uppers to 10 inch uppers that border on carbine-length territory, we have what you need.
Check this short guide then get the parts you need to start the build.
Why Build with an AR Pistol Upper in the First Place?
First, let’s cover why you might want to build an AR15 pistol in the first place, when you could just buy a full-size AR rifle or start with a full-size AR-15 upper.
As it turns out, there are numerous advantages to building a pistol-sized platform. Among these are:
- The compact size of an AR pistol, and the lack of a stock, result in a very small footprint. These are easier to conceal, and can be used effectively for defensive applications in tight quarters. They also make good truck guns.
- There are a wide range of calibers available in AR15 pistol uppers.
- You get the same firepower as a full-sized rifle in a smaller platform (many AR pistols are chambered in rifle calibers like 5.56/.223).
- Like full-sized AR rifles, they are easy to customize and upgrade.
- AR pistols are largely compatible with parts for full-sized rifles. Many parts and hardware are interchangeable between the two. Actually, on the note of compatibility, the following parts are often interchangeable:
- Gas system components
- Muzzle devices
- Barrels and handguards (assuming caliber and length are compatible)
- Charging handles
- Pivot pins
- Takedown pins
- Grips
- Buffer tube system components
- Lower parts
- The lower receiver itself
- Magazines
- Triggers and trigger guards
- An AR pistol has basically all of the advantages of a short barrel rifle, without the legal challenges, since it is considered a handgun and not a rifle.
So, with that covered, let’s talk about the different sizes available in AR pistol uppers.
5 Inch AR Pistol Uppers
Among the most popular AR pistol uppers are 5-inch AR pistol uppers. These are among the smallest of uppers, though 4.5 inch pistol uppers are also available.
Because these are so small, they are commonly available in 9mm chamberings, though .223/5.56 chamberings are also available.
Their small sizes means they are the best for concealment and maneuverability. At the same time, these small uppers result in pretty heavy recoil and muzzle pop.
Because the barrel is so short, not all of the propellant will deflagrate before the bullet exits the barrel, which means they run pretty dirty. It also means they won’t generate the highest muzzle velocities.
7.5 Inch AR Pistol Uppers
Next up we have 7.5 inch AR pistol uppers, which are also fairly popular. These are often chambered in .300 BLK, though they are also available chambered around other calibers.
The slightly longer barrel length means you will get more muzzle velocity. Since they weigh a little bit more, they will result in slightly less recoil (assuming the same cartridges are being compared).
Though they will result in a build larger than one completed with a 5 inch upper, they are also fairly easy to conceal.
10.5 Inch AR Pistol Uppers
Some might consider a build made with a 10.5 inch upper to be a carbine, but that’s really more in the realm of 16 inch uppers. A 10.5 inch upper is pretty short, more akin to a pistol.
Because these have longer, heavier barrels, you will get more muzzle velocity and less recoil, since the weight will help counteract that.
They will also be more stable, even though they will not be as light in the hard or as maneuverable in tight spaces as their smaller counterparts.
Also, they will not run as dirty as AR pistols made with smaller uppers/barrels.
Adding an AR Pistol Brace and a Suppressor
There are two important AR pistol accessories you should include with your build regardless of the size you go with.
One is an AR pistol brace also known as stabilizing braces. AR pistol braces are stabilizing fins that are used in lieu of stocks, that make it easier to shoot the platform and control recoil one-handed.
The other is a suppressor, one of the most valuable of all AR pistol accessories. Due to the short barrels, these platforms suffer from low muzzle velocity, high recoil and port pop.
A suppressor for an AR pistol is a game changer. It will boost muzzle velocity slightly, slash port pop and cut back on recoil.
Just be aware that suppressors are NFA items and that they will add weight to the muzzle, impacting handling by shifting the balance of the platform.
Starting an AR Build? We Have the Parts
Here for a 5-inch AR pistol upper receiver, an AR pistol brace or some other AR pistol accessory? Whatever you need for your build, we have it. Check out our collection or get in touch with us at Sales@MCSGearup.com if you have any questions.