Description
Carrying an immense punch in a single long-range shot, thus making the Magnum Shot skill appealing. The enemy wounded by this attack will collapse before they can even approach you. Not only that, even if it only grazes the enemy, this powerful skill will topple the enemy's morale and make them tremble in fear even before starting the battle. If you have reached the point where you can control the tempo in your concentration and the power of your attack, practice delivering a great impact on your target with this skill. This is easier said than done, however.

Details
A long-range, single-hit powerful attack. It is the ranged counterpart to Smash.
Will not knock down opponents using Defense with a shield equipped, given the shot does not kill or place the target into Deadly status.
Usable only with ranged weapons, which include a Bow and Crossbow.
Uses up one arrow per shot, regardless of whether it hits or not.
Aiming speed is slower than that of normal Ranged Attack.
When holding a bow, the user is slowed to a walk.
This also applies to Elves.
Elves can use Magnum Shot while mounted, but the mount will be slowed to a walking pace while the skill is active.
Giants cannot learn this skill.
When holding a crossbow, the user is able to run freely until the skill has finished loading. After the skill loads, the user is stationary until the arrow is fired or until the skill is canceled.
Starting from rank 5, the impact of Magnum Shot creates a splash effect.
The splash radius can be compared to that of a Mace (at rank 1, that of a Claymore) which affects all enemies, including hidden mimics, in a radial area.
The damage and wound are calculated separately to each enemy affected by splash.
The splash impact area is where the enemy was standing the moment you fired, even if the enemy runs around between the time shot and the impact.
Enemies hit by splash will not immediately aggro, even if their AI allows them to. Instead, they will be alert (!), walk closer to you, and use Defense or Counterattack depending on their AI. From there, if the enemy can multi-aggro, they will attack.
If the type of enemy does not have an alert state (ie. Skeleton), they will remain unaware of your presence.
The Player will have temporary invincibility right after firing magnum shot, however this is brief immunity and monsters can attack immediately as soon as the Magnum Shot animation is finished.

Obtaining the Skill
Human

To learn this skill as a human, you must have first at least achieved "Practice Rank" of the Ranged Attack skill.
Talk to Duncan about skills while having a bow equipped in the main weapon slot. You will learn the keyword "Magnum Shot".
Talk to Trefor about "Magnum Shot".
Talk to Ranald about "Magnum Shot".
Upon completing this step, you will then learn the skill.
Elf

To learn this skill as an elf, you must complete the beginner quest Eliminate Young Brown-legged Fennec Foxes.
Giant

Giants are unable to learn this skill.