It’s one of the biggest buzzes floating around the AR 15 realm (pun intended). Everywhere you look you see the terms “free floating barrel” and “free floating rail”. What does it mean? Why is it valuable? Is it worth investing in for a new build? These are all important questions you should be able to answer before adding more AR 15 accessories or AR 15 parts to your black rifle.
Does your AR 15 Need a Free Floating Rail?
Like most things, you have to decide: What is your build being used for? If you really want to push the accuracy of your rifle to the max then yes, you do need a free floating railed upper. These rail systems are exactly what they sound like: They “float” around the barrel, and attach to the upper receiver instead of attaching to the barrel itself, like a two-piece handguard does.
What's the Benefit?
When a handguard touches the barrel it will affect the accuracy of the gun. As you place tension on the handguard by gripping the weapon, you’re putting put pressure on the barrel. Even a little pressure on a barrel will affect accuracy at greater distances. Even though the barrel is made of hardened steel, it is still being moved due to its length and elasticity. A barrel that’s too rigid would also be too brittle and would crack quickly. You can learn more here.
There Are no Shortcuts
You’d think you could simply zero your gun with that two-piece handguard and everything will be fine, right? Well, unless you grip your rifle at the exact same angle, with the exact same amount of pressure, and grip the rifle in the exact same way, your shot groups will always be different. The variances will increase as the barrel heats up and becomes more malleable, too. This may not be noticeable at 100 or even 200 meters, but beyond that your ballistic coefficient will suffer dramatically. If you’re milling an 80 lower and slapping an upper on it to test the accuracy that you and a few good 5.56 rounds can put out, you need to consider a free floating rail system.
Free Float and AR 15 Accessories
A free floating barrel system is quite common when it comes to metal Keymod, M-LOK, and even some Picatinny rail systems. All a free floating handguard requires is a nut that’s at the forefront of the upper receiver. The rail installs over this nut and stays in place. The installation process is quite easy and these rails stay in place permanently, even with a single point of anchor. There’s also the additional benefit of barrel cooling because the free float rail system allows for increased airflow and less insulation.
There are a few minor downsides that are negligible for most people. If you prefer an A frame fixed front sight you can’t exactly use a free float rail system. The classic M4 style handguards and are non-compatible. Neither are Magpul’s polymer carbine fore ends. You are also generally isolated to the heavier metal handguards for a free floating barrel system.
Reach Out and Touch
A free floating barrel system on your rifle build will result in a more accurate weapon that is capable of producing tighter groups. Free floating rails systems are not expensive, and nowadays they’re quite common. They are also often very modular and easy to install. A free floating rail system is an excellent addition to any precision rifle build.DISCLAIMER: If you are new to the world of DIY AR-15 building, you likely have a lot of questions and rightfully so. It’s an area that has a lot of questions that, without the correct answers, could have some serious implications. We are by no means providing this content on our website to serve as legal advice or legal counsel. We encourage each and every builder to perform their own research around their respective State laws as well as educating themselves on the Federal laws. When performing your own research, please be sure that you are getting your information from a reliable source.