The cool part about building your own AR-15 is that you can be very selective on what parts you choose. Each and every part you pick has a significant impact on performance, comfort, and safety of your rifle but none more than the barrel.
The barrel matters a lot because it impacts how the gun feels when it fires. It’s one of the more expensive components, and it can be harder to change out once your rifle is completely assembled. Here are some things to look out for when you’re buying a new barrel:
The Rifling of Your Barrel
In your research, you may see people arguing over which type of rifling is better. Some will say that button-rifling is the way to go while others will argue about forged rifling. In reality, it’s all a matter of personal preference, and there isn’t one superior method.
If you’re looking for very precise accuracy, you’ll want to go with cut or button rifling. The Cold Hammer forged method tends to make barrels that have a higher tolerance to heat. When you’re talking about an AR rifle, longevity and resistance to extreme heat are probably going to be more important than pinpoint accuracy.
The Length of Your AR-15 Barrel Assembly
All barrels need to have a length of 16 inches to avoid a class 3 classification from the ATF but beyond that, it is a matter of personal preference and compatibility with AR-15 uppers. Your barrel length needs to be legal if you are using a rifle stock but just make sure you pay attention to regulations in your particular state.
Many common AR barrels are 16 inches but you can get a little extra velocity out of your gun with a slightly longer barrel. Of course, you want to make sure the barrel you get is compatible with your AR-15 upper assembly.
The Type of Steel
There is no right or wrong answer for this choice either. You want to look at the performance goals you have for your AR and then make your choice based on that. Although there are many variables, two important ones are barrel life and corrosion resistance. 416 Stainless Steel, for example, has amazing corrosion resistance.
If you’ll be using your gun outdoors a lot or live in an environment prone to metal corrosion, this might be a better choice. 4140 Chrome Moly Steel, on the other hand, is a little better for barrel longevity. They are harder than traditional stainless steel. Like with all guns, if you maintain them properly, they’ll hold up just fine no matter what.
Regardless of what choices you make for your barrel, just keep in mind that you should have your goals outlined first. Sometimes first-time shooters don’t really have an idea of what they like because they don’t have a lot of field experience so choosing something middle of the road will probably work. Typically after shooting friend’s rifles, people start to develop a preference either way on what types of AR components they want to use in their rifles.