Jedi Knight Galaxies uses a skill-based blocking system, where you hold down the block button and the attack button to go into "Projectile Blocking Mode". How well the projectile is reflected is dependent on how fast you hit the projectile in relation to going into Projectile Blocking Mode. So if you go into PBM very soon (or literally right before) the projectile hits you, it will reflect the missile right back at the attacker, although this is very hard to do as a beginner Jedi character (ie, without any points in blocking skills) and you'll almost certainly be dead if you try this with repeaters. If you just hold the PBM, you will stop being able to block projectiles after a period of about 5 seconds, so you need to constantly go into and out of PBM. Higher-levelled Jedi characters can just hold the button for passive blocking. Of course, in order to reflect shots, you will still need to block accurately in this case.