The Argument for 7.5” Uppers

AR pistol builds, thanks to their compact footprints, concealability, lightweight and maneuverability, are becoming more popular.

Add to that the fact that you don’t need to make a concession on chambering if you don’t want to, and you can make a pistol-sized platform with rifle-sized firepower.

But there are many different sizes in uppers and barrels. Which is the best?

That will depend on your ultimate purpose for the build, but if you’re looking for a good balance across all attributes, a 7.5” upper is a good bet – here’s why.

What a 7.5” Upper Will Deliver
An AR pistol built from a 7.5” upper will be naturally more compact than one made with a 10” upper and ever so slightly bigger than one made with a 5” upper.

In short, the 7.5” will offer a little bit of the performance of both without making any serious compromises.

A 7.5” barrel will naturally substantially lighten the overall build, while still offering enough space on the handguard for shooting attachments and accessories.

Though they are slightly larger than AR pistols made with 5” builds, those made with 7.5” uppers still offer excellent concealability and handling. They’re light and nimble, much more so than those made with 10” barrels.

They win on handling, and the cool thing about short barrels is that they are not nearly as inaccurate as some people would have you believe. Though the bullet has less distance to engage the rifling, longer barrels tend to have less consistent harmonics.

Therefore, the barrel whip of longer barrels can actually, in effect, throw accuracy off. Not so with shorter barrels.

So you lose nothing on accuracy, but you gain on handling, weight, and maneuverability, especially with respect to concealment and engagements in tight spaces.

So is there anything not to love about a 7.5” upper?

Are There Drawbacks?
Before covering these, it is important to fully understand that the drawbacks that will be mentioned here in no way detract from the utility of an AR pistol. They are just realities that must be considered.

For one, the shorter barrel doesn’t give the powder enough time to fully deflagrate in the chamber and bore.

Therefore, a 5.56 round fired from a 7.5” barrel will be slower and deliver less muzzle energy than the same exact round fired from a 16” or even a 20” AR rifle.

As a result you will lose a marginal amount of firepower. Just something to consider.

One more thing of which you should be aware is that the same conditions will result in a much dirtier platform. Expect to encounter a lot more fouling in your bore chamber, and in your gas system and around your BCG if you build a smaller AR pistol.

One more thing is that, since these platforms are smaller and lighter, recoil will naturally be a bit more pronounced. It probably won’t tip the scales too much with a caliber as meager as 5.56 or .223 Remington, but it is still something to consider nonetheless.

Where to Get a 7.5” Upper for Your Build
Looking for parts and assembled uppers for your next AR pistol build? Get them online at MCS Gearup.

MCS Gearup carries a wide range of AR parts and AR build kits, including short barrel uppers like 7.5” uppers (among other assembled uppers). They also carry parts, attachments, and shooting accessories.

Take a look through their online catalog to learn more and if you have questions about part specifications or compatibility, get in touch with them at

For more information about Mck and Ar15 Pistol Upper Please visit: MCS Gearup.