There are two variants here, LRMs and SRMs.

LRMs: Long range missile launchers fire missiles that have limited tracking capability. They are accurate, but lack timing capabilities and so don not have the pinpoint precision of Streak Missiles. Ammo is limited. LRMs have a minimum range of 90 meters. If they hit before they have traveled their mimimum range, they will not explode, although they may do slight impact damage.

SRMs/Streak SRMs: These direct-trajectory missiles are more powerful than long range missiles, but only accurate at short range. The Streak variant has a smart targeting system that prevents it from being fired unless it is locked on and almost guaranteed to hit. Ammo is limited