The AR-15 platform has been referred to in earnest as the “Swiss Army Knife” of rifles. It’s a good moniker.
There’s a lot of truth in the statement, too. Leave alone the fact that the rifle itself is adjustable and the platform can be built around a wide range of rimfire and centerfire cartridges.
Even were it not for that, the presence of adequate rail space and attachment points makes it fairly simple and straightforward to upgrade the handling and capabilities of the rifle with vert grips, lights, lasers, optics, side saddle mounts, and so much more.
Plus, the fact that AR15 parts are widely compatible with so many different builds makes the platform even more versatile.
On top of that, tinkerers have a lot of options when it comes to different AR15 parts, especially if they’re building their own platform.
An AR-style rifle can be completely customized from the ground up in extraordinary piecemeal fashion.
One question that must be asked has to do with AR15 upper receiver length. These rifles are configurable with both long and short uppers (barrels, really) but which is best?
As is often the case with AR-style rifles, there is no single best part. Therefore, the best AR15 upper receiver (with respect to barrel length) will depend on your prerequisites.
One Size Does Not Fit Most
When you’re shooting a shotgun, there is no best choke. You might want to use a full fixed choke when hunting coyotes or turkeys to concentrate the pattern in a small area. On the flipside, you might opt for an open choke when shooting skeet to increase forgiveness and boost your chances of a hit.
The same thing goes here. There is no one size fits all when it comes to a platform as modular, and as versatile, as the AR-15.
So, to answer the question of which is the best AR15 upper receiver in terms of barrel length, we need to break it down to a few fundamentals. There are three common barrel lengths, which are 16”, 18” and 20” (although longer barrels are available).
Here’s what they offer and the situations in which a longer barrel would be better compared to when a shorter barrel would be.
When a Longer Barrel Is Better
The first AR-15 was designed with a 20-inch barrel, which was intended to produce higher velocities than shorter barrels, resulting in favorable terminal ballistics at greater ranges.
The longer the barrel of an AR-15, the greater the velocity, and the longer the sight radius. This produces a few desirable effects.
One is that the rifle will produce higher muzzle velocities. This results in less bullet drop at extended ranges (beyond 100 yards) making AR15 builds with longer barrels more suitable for shooting at greater ranges.
The longer sight radius also makes it easier to aim the rifle, meaning you will be able to shoot more accurately over iron sights, all else being equal. This is irrelevant if you pair your rifle with a red dot or optic, though.
In addition to the fact that the longer barrel will produce greater accuracy and less bullet drop at extended ranges, it’s also a bonus that it produces higher muzzle velocities, too, especially if the rifle is chambered in 5.56 or .223 and its intended use is hunting.
This is a low-powered, mini-action cartridge. If you’re hunting at extended ranges, you likely need all the power you can get, and the longer barrel will assist with that.
The long and short of this is (no pun intended) that the best AR15 upper for shooters that hunt or compete at longer ranges (in excess of 100 yards) is one that has a longer barrel - say, 20”.
With that said, there are also AR15 uppers with barrels longer than 20”. If your most important considerations for the rifle have to do with long-range accuracy and performance, opt for an upper that has a barrel of 20” or longer.
When a Shorter Barrel Is Better
At the same time, the best AR15 upper is not unequivocally a long one. There are many instances in which a rifle with a 16” or an 18” barrel (mid length) would be preferred.
The 16” AR-15 barrel is one of the most popular and also the shortest one that can be legally owned without having to cut through all the red tape associated with owning an NFA item (if it has a barrel of less than 16” it would be considered a short-barreled rifle).
It can be said that an AR-15 with a 16” barrel will have a shorter sight radius, making it harder to shoot accurately over iron sights. The shorter barrel also does not produce the same muzzle velocities or accuracy, making it less reliable when shooting out past 100 yards.
However, an AR-15 with a 16” barrel will be lighter, less muzzle heavy, and much more maneuverable than a rifle with a 20” barrel. This makes it easier to handle and point them in close quarters.
This gives AR-15 platforms with shorter overall uppers an edge in situations in which handling and maneuverability are essential. If your rifle is intended for defensive applications, competition at close ranges, or hunting in brush (like hog hunting) the shorter barrel might be better.
At close ranges, the extra ballistic efficiency is really not necessary; what’s necessary is connecting with a shot, and a shorter barrel will improve handling and increase the odds of that.
Besides, the extra power is hardly needed at close ranges and within 100 yards there’s effectively no difference in accuracy, anyway - so again, if you intend to build an AR-15 for defensive use or up-close competition or hunting, a shorter barrel is better.
Shop the Best AR15 Upper Receivers Here
Looking for the best AR15 upper receivers? We carry a wide range of high-quality options in a wide range of lengths and other configurations.
In addition to a wide variety of AR-15 upper receivers (including complete uppers) we also carry stripped uppers and sundry parts, including but not limited to ejection port dust covers, gas systems, muzzle devices like flash hiders, charging handles, and complete bolt carrier groups.
Take a look through our collection of assembled uppers via the previous link and get in touch with us at Sales@MCSGearup.com if you have any questions.