Rails & Handguards

A handguard does three jobs: it keeps your hand off a hot barrel, it gives you somewhere to mount lights and bipods, and on a free-float design it removes contact between the barrel and anything you are gripping or resting on. That last one is the accuracy argument, and it is real.

M-LOK has become the dominant attachment standard, having largely displaced KeyMod, and it lets you put Picatinny sections only where you need them instead of carrying rail all the way round. Length is a handling decision — a longer handguard lets you get your support hand further out for better control. Installation usually means removing the barrel nut, so check what tools the design requires.