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AR 15 Size - Gun Case Sizing Guide

AR 15 Size - Gun Case Sizing Guide

Posted by Gunbuilders.com on Sep 11th 2023

AR-15s, or America’s rifle, come in a variety of configurations: modern M4 clones, the typical 16"-barreled rifle with an M4 buttstock, fixed-stock variants, pistols and SBRs, and long bench guns nominally chambered in either .308 or 6.5 Creedmoor. You also have to contend with all the optics normally fitted on those flat-top uppers, even the occasional carry-handle receiver.


Typical AR-15 Dimensions

For our tests of new rifle pistols, we assume each uses a conventional receiver. This is a mil-spec configuration with standard lower components and tubes. Custom chassis and ultra-small buffers can vary in length compared with standard chassis configurations or super compact ones. We're breaking down the typical lengths and dimensions found on most AR-15s, so you can better select the one rifle case for you.


16"-Barreled Rifle w/ Collapsible Stock


Virtually all AR-15s sold in stores or bought by first-time owners are configured similar to what's shown above. This is This is considered a civilian mil-spec rifle, which means it comes with a forged pair of upper and lower receivers (where the barrel is attached), a mil-spec buffer tube, and A2-style flash hider, and a typical M4-type buttstock. All these features are standard on most military-grade rifles.

The M16 is a gas-operated, semi-automatic rifle that uses a direct impingement gas operating system. It is chambered for the 5.56x45mm NATO cartridge and can fire in both semi-automatic and three-round burst modes. The M16 was first introduced in the 1960s and used by the US army ever since.

What length of AR is best?

A 20-inch barrel is an effective way to maintain velocity while ensuring the bullet is stabilized and supersonic for as much time as possible for accurate shooting. The minimum length for the barrel of M16, by law, is 16" (which is 2" longer than the barrels of service-issued rifles).

Aside from a 30-round magazine attached to the lower receiver and a Trijicon ACOG front sight equipped on top, the M16 also has the following dimensions:

  • Overall length (buttstock collapsed): 32.75"
  • Overall height (receiver to end of magazine): 8.75"
  • Overall height (with optic mounted to upper): 12.25"

The Trijicon ACOG is 3.62" tall, and we think that using this as a measure for how wide your AR 15 should be is a safe and reliable guideline. If you want to be able to keep your scope without having to remove it from the receiver, most 1" or 30mm scopes with scope rings installed on a flattop upper will measure around this height too.

Recommended Case

For the AR 15 configured in the standard way, we would suggest using a 36" case that is 10" wide at the minimum to ensure optimal protection for your firearm. The Boyt H-Series Hard Case would be a great choice to protect your firearm while in transit or storage.


It measures 36" long by 13.5" wide, with a 4.5" depth and plenty of padding for your rifle. With the stock collapsed, it'll fit any 16"-barreled AR with room to spare for red dots optics, ammo, handguard attachments, and accessories. It's also waterproof and includes a pressure equalization valve to ensure it remains sealed in any environment. This case also features multiple locking points for added security, which can be locked with padlocks.


AR Pistol / 10.5" SBR

The AR 15 pistol has become popular in the market, and its dimensions (and the choice of optics of the end user) tend to closely match the AR-15 short-barreled rifle. This makes the AR-15 pistol a handy tool for close-quarters combat, as it is much more maneuverable than the rifle.

This AR 15 Pistol has the mil-spec. It has a 10.3" barrel and an A2 flash hider. Additionally, it is also equipped with an aim point-type red dot sight that is approximately 3.75" tall. This combination of features specifically makes it much better suited for close-quarters combat than other types. The product dimensions are as follows:

  • Overall length (buttstock collapsed): 26.75"
  • Overall height (receiver to end of magazine): 8.75"
  • Overall height (with optic mounted to upper): 12.50"

The barrel length of pistols and SBRs can vary from 14.5" for M4 clone builds to 4.5" for pistol-caliber carbines. Likewise, AR pistol braces are typically larger than the rifle stock found on an SBR. This is because an AR pistol brace is designed to be used as a shooting rest, while an SBR stock is not.

The length of the barrel is determined by two factors, which will affect the overall length. We chose the 10.3" Mk18 as an example, because lengths ranging from 9.5" to 11.5" tend to be the most common on conventional AR-15 pistols and SBR builds.

Recommended Case


Since pistols and SBRs are the shortest AR configurations, something like the Boyt case suits your shorty. The Plano All Weather Case is 36 inches long, like the Boyt, but it is narrower and 5.5 inches deeper. Pistol braces tend to be wider than buttstocks, so the extra depth helps store larger items.


A2-Type/Fixed Stock AR-15 ("M16" Clone)

For those who love the old-school AR look, we didn't forget about you. This is an M16 clone, which sports a much longer barrel, measuring 20". Its fixed stock, often referred to as an A2 stock, is also much larger than the modern M4-type collapsible stock. Lastly, it doesn't use the conventional flat-top upper receiver with a Picatinny rail. Instead, it uses a carry handle with integrated rear iron sights, which also adds to the height. Even though this clone is pictured with an original 20-round magazine, we're taking measurements with a 30-round magazine factored in for precision.

This configuration reports the following dimensions:

  • Overall length (buttstock collapsed): 39.50"
  • Overall height (receiver to end of magazine): 8.75"
  • Overall height (with carry handle installed): 10.75"

The dimensions of a fixed stock are approximately 10.625" long and 5" tall at its widest point. This is significantly different from the AR-15's standard M4 configuration, which has a collapsible stock. If you're debating converting an existing AR-15 to an A2 configuration, take this into consideration.

Recommended Case


Plano's All Weather Case comes with enough length and width to snugly fit this A2-type configuration. With the 42" Version, you have enough padding on either side of your rifle to keep it safe from bumps and scrapes. The same 13" width as its smaller variant provides enough height to store the carry handle with a 30-round mag well in the magazine, making it a perfect choice for those who want a bit more height without sacrificing portability.


AR-10 / LR-308 (.308-caliber ARs)


We understand that there are many people who still prefer to use .308 or bench rifles. If you're one of those people, you're probably using an AR-10 with a 20" barrel. That's the most common length found on .308 ARs, although the longer bolt and receivers also add some extra length compared to an AR-15. For example, an AR-10 is typically about an inch longer than an AR-15. Thankfully, though, most AR-10s and LR-308s still use AR-15 buffer tubes and buttstocks.

To ensure you purchase a long enough gun case, we figured it would be best to use the most extreme setup as an example. The AR's .308 receivers are 1.25" longer than the AR-15's. With a 20" barrel, this rifle is 40.5" long, weighs 7.8 lbs unloaded, and has a 20 round ammo capacity.


Dimensions:

  • Overall length (buttstock collapsed): 42.30"
  • Overall height (receiver to end of magazine): 8.00"
  • Overall height (with optic mounted to upper): 11.50"

If you're wondering why this has less height than the AR-15, well, it does. Most.308 ARs use 20-round magazines, which are slightly shorter than the AR-15's 30-round magazine. 30-rounders are available for purchase; they are 3.25" taller than a regular one, and with them, the rifle's height becomes 11.25". Without an optic, of course.

Recommended Case


We would once again recommend something like Plano's All-Weather Case. This is the 52" Version, which provides plenty of space for any AR-10 or LR-308, especially if you're running a gun chambered in 6.5 Creedmoor (which can take advantage of a barrel up 24" long). You'll probably want some extra room for accessories, especially if you're using a larger, variable-power scope, and a bipod. Plano's larger models come with the same waterproofing and locking features as the smaller versions.


Is the AR-15 good for hunting?

Yes, it can be used with lightweight or powerful guns if you want to hunt a lot of large game with a medium to softer size. An AR can be used in armed combat situations with less risk and more effective performance in comparison to conventional bolt carrier rifles.

Fun fact: Many firearms do not fall into the safety category in hunting. AR-15s are safer. Besides their ability in fighting the rigors, they are also strong in the field against extremes of weather or rough terrain. Where your old wooden rifle swells, warps, and loses its grip or wanders, it is precise and able to shoot in any circumstance.

When considering an AR in the near future, you must take into account many different dimensions, such as length, width, and height. Here is a quick recap of the most important measurements to remember to make selecting the right AR case a little easier:

  • The average AR 15 with a 16"-long barrel measures approximately 32.75" from the muzzle devices to the buttstock.
  • It measures about 8.75" tall, from the top of the receiver to the bottom of the magazine.
  • The average AR pistol or SBR measures less than 30" averaging 22" to 27" in length.
  • The average AR-10 or LR-308 rifle measures about 40" to 43" in length.

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