After exploring how the Covenant Carbine works in great detail here, I have decided to continue my semi-official Covenant Weapons blog project with a dissertation on the Type-33 Guided Munitions Launcher, or as it is more commonly known, the Needler.
As we all know, the Needler fires long, crystal-like projectiles that stab into the target, causing damage much like a bullet. Unlike bullets, however, they will explode seconds after impact, so if the impact doesn't kill you, the big bang will. Through an unknown mechanism, the Needles can also track targets, much like a guided missile, which points to them being self-propelled, an observation reinforced by the fact that the Needles leave a long coloured trail behind them as they fly. Rocket exhaust, perhaps?
So, I believe that the Needler works on the following principles: When the Needler's trigger is pulled, one of the Needles on the top of it is pulled into the weapon and pushed into a (very short) firing chamber at the front of the weapon. While this is happening, targeting data from an IR camera above the Needler's barrel is being fed into the miniturised computer onboard the Needle, giving it the user's target. All this takes less than a second. Once the data has been recieved, a miniturised rocket engine (possibly plasma-based, given the Covenant's penchant for that kind of technology) fires and the Needle bursts out of the firing chamber, the onboard computer tracking the target's thermal signature and altering course as necessary. Finally, the Needle will slam into the target, activating a delay fuze that gives the Needle extra time to penetrate, thus causing even more damage now and when the explosive goes off. After a second or two, the fuze detonates the Needle's explosive core, shattering the Needle and wrecking the unfortunate target with crystalline shrapnel and blast damage.
This all sounds far too complicated for a small arm, but we have seen before that the Covenant are an extraordinarily advanced (technologically, if not socially) culture that should have no problem in developing something like this. Why though, they make the projectiles glowing, highly-visible crystal needles that leave a trail behind them, thus making them worse than tracers for tracking the firer, I cannot say, but we have also seen before that the two most important guiding principles for Covenant military doctrine are "Rule of Cool" and "Honour Before Reason". Perhaps the crystalline shape aids in fragmentation within the target when the Needle explodes.
So, there we have my mildly interesting and somewhat unrealistic opinion on the mechanism of the Needler. No off-topic comments, please!