A handguard determines three things on the AR-15: where your support hand sits, what you can attach in M-Lok slots, and how the rifle balances across different shooting positions. Getting these right matters most in 3-Gun and field-course competition, where you move between shooting positions, engage targets at different heights and distances, and need the rifle to handle consistently in every orientation. The AR-15 is designed to have its handguard replaced -- the modular platform expects it.