Kig-Yar point defense gauntlet
From Halopedia, the Halo wiki
Jackal Point Defense Gauntlets are used by Jackals for protection from enemy fire. Worn on the forearm, they create a barrier that can deflect any solid projectile weapon except rockets.
Damage Resistance
The shield of the point defense gauntlet reflects it's current charge by changing color gradually from its original color to red before it deactivates completely.
Conventional Weapons
The Jackal Point Defense Gauntlet is completely resistant to ballistic ammunition. All UNSC weaponry will simply bounce off the shields. Even the SRS99C-S2 AM Sniper Rifle's large 14.5mm APFSDS are deflected. However the MA5B and SMG rounds will eventually cause the Jackal to flinch and momentarily lower its shield, allowing the rest of the weapon's bullets to eliminate the Jackal. This may be due to the physical weakness of the Jackal.
Plasma Weapons
Plasma-based weapons on the other hand, will collapse the shield altogether. Continuous fire from a Plasma Rifle or a Plasma Pistol overcharged shot will successfully collapse the shield and may also cause the jackal to flee.
Grenades
It should be noted that grenades, even though deflected by the shield, can still explode and collapse the shield if detonated nearby.
Melee
The most effective and efficient way to kill a Jackal is with a melee attack. A direct hit to the shield will often 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.
Halo 2 changes
In Halo 2, the shield appears to have been weakened. It is now possible, but difficult, to bring down a shield with projectile weaponry, and a sniper round to the central dot will collapse it and stun the Jackal. However, the shield now provides the Jackals with limited melee protection.
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, when you zoom in with the Plasma Pistol, the outline is in the shape of the Jackal's Personal Arm Shield from Halo: Combat Evolved, except that it is horizontal instead of upright.