The AR-15 family of guns has become “America’s Rifle” over the period of almost 60 years. Over time, the rifle has seen many changes and refinements. Now that there are so many choices, prospective buyers and users could use some determining what choices are best for them. This article has four sections covering: rifle configurations/parts selection, ammunition, rifle accessories, and rifle cleaning/maintenance. Hopefully, you will find some of the information below helpful.

Rifle configurations and Parts selection

The first thing to decide is whether you want to build or buy a rifle. If you are on a strict budget, definitely buy your rifle. Similarly, if you plan on only having one or two AR-15 rifles, buy your rifles. It will not be worth the cost to invest in the tools that are needed to build a couple AR-15 rifles. One of the biggest reasons to build your own AR-15 is that you are able to pick the exact parts and configuration that you want for your rifle. Then, you won’t have to waste money on parts that you will change out later.

The next choice to make is whether you want an M4 style rifle or free floated barrel style rifle. The designation “M4” is a more modern variant of the AR-15 family. The M4 style rifle is usually cheaper if you are on a budget. This rifle style has a pinned front sight gas block. The front handguard is held between the gas block and the delta ring on the front of the upper receiver. The handguard can put pressure on the barrel all the way out to the front sight gas block. Therefore, the barrel is not free floated. A Free Floated style rifle has a tubular handguard that attaches rigidly to the front of the upper receiver and does not touch the barrel or gas block. The barrel only has contact where the barrel meets the inside of the upper receiver.

A free-floated barrel can potentially have better accuracy because the handguard does not have the ability to place varying amounts of pressure on the barrel like the M4 does. Keep in mind, a M4 style rifle is typically plenty accurate (the US military uses it) and a free-floated barrel is not absolutely necessary. Depending on the rifle and ammo, you should be able to achieve 4 MOA (4 minute of angle, all bullets within a 4” circle at 100 yds). A free floated barrel has the potential to achieve 1 MOA accuracy. This level of accuracy is not required. Bear in mind, some M4 style rifles may be able to achieve 1 MOA with quality ammunition. Additionally, free floated barrel style rifles typically have more top rail space and handguard accessory space.

Next, choose the chamber type for your rifle. The main choices are .223 Remington, 5.56x45mm, and .223 Wylde. There are many other specialty chambers available. However, they are not within the scope of this article. The standard .223 Remington chamber can only safely shoot .223 ammo. It cannot safely shoot 5.56x45mm (aka 5.56 NATO). The .223 and 5.56 cartridges are theoretically dimensionally the same. However, 5.56 cartridges can be loaded to higher pressures and a 5.56 chamber inside the barrel of the gun has critical dimensional differences. The 5.56 chamber has a larger bullet lead to the start of the rifling (barrel free bore and taper) that helps reduce chamber pressure with the higher pressure 5.56 round. Due to the larger bullet lead, a 5.56 chamber theoretically may be less accurate than a .223 chamber. The .223 Wylde chamber is a hybrid chamber between .223 Remington and 5.56x45mm. This hybrid chamber reduces the 5.56 chamber free bore while still maintaining safe chamber pressures. You can shoot both .223 or 5.56 cartridges in a .223 Wylde chamber. Theoretically, the .223 Wylde chamber could potentially be more accurate than a 5.56 chamber.

The next choice for your rifle should be barrel length, gas system length, barrel twist, and barrel profile. First, barrel length should be considered for your planned usage. I would recommend either a 16” barrel or 14.5” with pinned and welded muzzle device to make the barrel at least 16”. Any rifle with a barrel of less than 16” is considered a “short barreled rifle” (SBR) by the ATF (Bureau of Alcohol, Tobacco and Firearms) and is illegal to possess without a National Firearms Act (NFA) tax stamp. As long as the pinned and welded barrel/muzzle device is longer than 16” in total length then it is not an SBR. You used to be able to purchase a 10” or 14.5” AR pistol with a pistol brace on it. However, the ATF recently changed the rules for pistol braces. In my opinion, any barrel length longer than 16” is just added weight on an AR-15.

The gas system length is important for the proper function of your rifle. If you have a gas port too close to the chamber of the barrel and not close enough to the muzzle end, you may have higher barrel chamber pressures at time of extraction causing harder extraction and a harder recoil impulse. This issue is sometimes referred to an over-gassed rifle. A gas port that is closer to the end of the barrel allows the bolt of the gun to unlock at lower chamber pressure, forcing the bolt and bolt carrier backward at a lower velocity. You may not have a choice in the gas system length if purchasing a rifle, especially the M4 style. Unfortunately, any M4 style rifle that you purchase will most likely have a less than ideal gas length for a 16” barrel. Due to a set handguard length for carbine handguards, you will most likely have a carbine length gas system.

Ideally, a 16” barrel will have a Mid-length gas system. The original M4 used by the military had a 14.5” barrel with the carbine length gas system. To comply with NFA rules regarding rifles not being short barreled rifles, the barrel was lengthened to 16-16.5” but kept the same carbine gas length. The Mid gas length is a relatively newer development in the history of the AR-15. It is better optimized for a 16” barrel. For barrels 18”-20” in length, a rifle length gas system is ideal. A 14.5” barrel should use a carbine length and a pistol of 10” should use a pistol length gas system.

Many common issues with the AR-15 revolve around the gas system. An over gassed rifle may show symptoms of throwing brass between the 1 o’clock and 3 o’clock position if the muzzle direction is considered as 12 o’clock. Additionally, over gassed rifles may have a failure to properly extract a spent shell casing since the bolt unlocks “early” at higher pressure before the brass case has the opportunity to relax at a lower chamber pressure. This can potentially cause the next round to not properly chamber. Additionally, increased extractor wear may become an issue. If you have a factory built 16” M4 style rifle with a carbine gas system, your rifle will most likely function fine. If your rifle is over gassed, then you can install a slightly heavier buffer to counteract the issue and improve the bolt unlock timing.

Barrel twist should be appropriate to the bullets you plan on using in the cartridge. I would recommend a 1-9” or 1-8” twist barrel to stabilize higher grain bullets. The 1-9” will stabilize up to around 69 grain bullets and the 1-8” will stabilize even heavier. Keep in mind a fast twist barrel such as a 1-7” twist may not work well with lower grain bullets such as 55 grain and below. Personally, I would recommend 1-9” barrel twist. I would plan on shooting anywhere between 55gr and 69gr bullets. However, you may want to shoot up to 77gr bullets because of the higher damage some heavier rounds can do.

Barrel profile is an important choice. If you purchase a rifle, you will not have much choice in the matter. However, barrel profile is important in keeping the weight of your rifle reasonable. In my opinion, do not buy a chunky and thick “government profile” barrel. You don’t need that thick of a barrel. The “government profile” was created for fully automatic magazine dumps, so it is definitely not necessary and not worth the weight. Hopefully you can find a medium profile that tapers toward the end. The thinnest barrel profile is commonly referred to a “pencil” barrel. Pencil barrels will tend to heat up quicker and potentially temporarily lose accuracy more quickly due to heat. One barrel style with more thickness, but less weight and better heat exchange is the fluted barrel. It starts as a thicker barrel but has groves machined into the outside of it reducing weight and increasing surface area for cooling. The drawback to the fluted barrel is that the extra machining causes the barrel to have a higher cost than a non-fluted barrel.

Choosing a factory-produced rifle can be overwhelming with all the choices. For a budget rifle, I would suggest three different rifles: the Ruger AR-556, Smith & Wesson M&P 15 Sport II, and the Palmetto State Armory PA-15 M4. These are quite solid and reliable beginner choices in the $500 – $750 price range.

In my opinion, one of the biggest mistakes made in the building/factory design of the AR-15 is not considering that it was originally designed to be a light and handy rifle and there is no reason why it can’t still be light today. The AR-15 doesn’t need to be a 10-lb rifle like an old M1 Garand firing 30-06. If you are smart with weight, you can add nice features to your rifle and still not make it into an 8-9lb rifle.

(To be continued tomorrow, in Part 2.)