Kig-Yar point defense gauntlet

Jackal Point Defense Gauntlets are linear energy shields mainly used by the Covenant Jackals for protection from enemy fire. Worn on the forearm, they create a barrier that can deflect most solid projectile weapon.

Damage Resistance
The shield of the point defense gauntlet reflects its current charge by changing color gradually from its original color to red before it deactivates completely.

In Halo 2, the shield appears to have been weakened. It is now possible (albeit difficult), to bring down a shield with projectile weaponry, and a sniper round to the central dot will collapse it and stun the Jackal.

Halo 3 era jackal shields are identical to the ones in Halo 2 except that a melee will now collapse the shield.

UNSC Weapons
The Jackal Point Defense Gauntlet is completely resistant to the UNSC's metallic projectile ammunition. Most UNSC weaponry will simply bounce off the shields. Even the SRS99C-S2 AM Sniper Rifle's large 14.5mm APFSDS are deflected (except when fired at the central shield emitter).

However continuous fire from certain weapons will cause the Jackal to momentarily drop its shield. The Warthog's M41 LAAG, AIE-486H Heavy Machine Gun (and curiously MA5B and SMG) rounds will cause the Jackal to flinch allowing the rest of the weapon's bullets to eliminate the Jackal. This may be due to the physical weakness of the Jackal as the bullets themselves are deflected.

The few human weapons that can penetrate the shield are explosive weapons such as the Rocket Launcher, missile pod, and the Spartan Laser.

Covenant Weapons
Alternatively, the point defense gauntlet has very low resistance towards Covenant Plasma-based weaponry. Plasma fire will deplete the shield's strength until they completely collapse. A few shots from a Plasma Rifle or a Plasma Pistol overcharged shot will successfully collapse the shield and may also cause the Jackal to flee.

Strangely the Covenant Carbine, a projectile weapon, can also deplete the shield.

Grenades
Explosions from grenades can collapse the shield and kill the Jackal. It should be noted that the Plasma Grenade and the Spike Grenade will not stick to shield but can still destroy the shield and the Jackal if it's near the explosion.

Melee
In Halo: Combat Evolved a direct hit to the shield will knock it backwards into the Jackal, sending a power surge through the Jackal's body and killing it. However, on Heroic and Legendary, it will often take more than one attack. Similar to most enemies, Jackals flinch when hit with a melee attack. In Halo 2 the shield now provides the Jackals with limited melee protection but in Halo 3 a melee attack will collapse the shield.

Trivia

 * In the first Teaser of Halo: Combat Evolved a group of UNSC Marines inside a Forerunner complex engage with a Major Domo Elite with a triple-layered personal arm shield similar to the Jackal's.
 * In Halo 2, the Arbiter's zoom outline resembles that of a horizontal Jackal Energy Shield from Halo 1.
 * Sniper Jackals wear point defense gauntlets but never use them, even after dropping their rifles or carbines and fleeing.
 * It seems that Half-Jaw has his own personal arm shield. This can be seen in the Halo Graphic Novel.

Related Links

 * Energy Shields
 * Overshield
 * Elite Personal Energy Shield
 * Jackals
 * Shielded Flood Carriers