Choosing the suitable length of handguard can be crucial when building your rifle. It will affect the performance of your firearms and even your safety when shooting.
Things To Consider
We're talking about free-floated handguards here because you can determine the length of them. You are only able to use the length that your FSB compels you to use because drop-in handguards rely on the front sight block to attach to the rifle. With free-floating handguards, you can choose the endpoint because they just attach to the receiver.
Length of Barrel
In most circumstances, the length of your barrel will determine the longest possible length for your handguard.
You will probably have a hard time if your handguard reaches beyond your barrel. First of all, it poses a safety risk because your hand could get burned.
Second, there is a good risk that your handguard may be harmed or destroyed.
If you intend to use a muzzle device that extends past the end of your muzzle and does not have ports to guide gases to the side, this rule does not apply to you.
I suggest you consider the length of your gas system to be the minimum length of your handguard.
The gas tube is the one component of an AR-15 that has to be protected. If you have a gas system that is rifle-length but a handguard that is only pistol-length, you are exposing many inches of the bare gas tube.
After you shot, if you or anybody else touches it, it will burn horribly.
It is also a crucial component that might get dropped or hit. The gas tube cannot operate if it is damaged, broken, or deformed. You can’t shoot with it until you fix the tube.
Smaller and lighter designs benefit from a shorter handguard, but having an exposed barrel at the end makes it more difficult to shoot off barricades if desired.
Resting off the barrel causes POI changes and is unpleasant.
Additionally, a longer rifle allows you to hang more items from it. IR/visible laser, foregrip, and any other accessories you might wish to install.
If a bipod is an essential part of your build, mount it as far outside as you can.
The same for iron sights; longer length is always preferable.
Some suggested length options
These can be used securely on pistols, carbines, mid-length gas systems, and barrels that are at least 10.5 inches long.
Suitable for pistol-length gas systems as well as mid- and carbine-length systems.
Your minimum barrel length is 12.5 inches, which accommodates a wide range of popular barrel types, including the 14.5-inch model, which is highly popular.
It works great with any standard-length gas system despite being primarily designed for rifle-length gas systems.
These are perhaps the most typical lengths for handguards and are typically only used on barrels that are 16 inches or longer.
Overall, Free-floating handguards provide a variety of alternatives, let you modify your rifle to better suit your needs, increase mechanical accuracy, and provide mounting points for accessories.