Mass Effect Wiki
Mass Effect Wiki

The M-300 Claymore Heavy Shotgun is a shotgun in Mass Effect 2 and Mass Effect 3.

Mass Effect 2[]


Very rare krogan shotgun. Deals high damage at short range; less effective at long range. Effective against armor, shields and biotic barriers. It is of human design but is only used by krogan, due to the fact that the kickback from a single shot has enough force to break a human's arm. Protected by Fabrication Rights Management (FRM) technology, this weapon is nearly impossible to reproduce and is prohibitively expensive.


  • If playing as a Soldier or a Vanguard, the weapon can be obtained during the Collector Ship mission.
  • After recruiting Grunt, asking him about upgrades will make the M-300 available for research as a weapon for him. Only Grunt can use this Claymore.

Player Notes[]

  • The M-300 only holds one round per thermal clip and a limited amount of spare ammunition. Coupled with its short-range and high damage, these qualities make the M-300 a "high-risk, high-reward" weapon.
  • The Claymore's fire rate can be improved by holding the fire button and performing a melee attack on hearing the click sound during reloading (aka "reload cancelling"). While this can be performed with any weapon, the Claymore gets a relatively higher benefit from the technique due to its single-shot magazine.
    • This reduces the delay between shots from 2.4 seconds to approximately 1.4 seconds.
    • This can be repeated to maintain a constant improved fire rate.
  • Grunt is the only squad member who can wield the M-300 and he deals 40% less damage with the weapon than Shepard.
  • For Vanguards, when used with Heavy Charge, the time-dilation can allow the player to inflict massive damage by immediately following up a Charge with a precision point-blank range shot, all before the enemy has time to react.
  • The Claymore becomes less useful on higher difficulties when one-shot kills are more difficult to accomplish. It can reliably one-shot varren, FENRIS Mechs, and Husks even on Insanity if given anti-armor ammo powers.
  • The damage boost of Heightened Adrenaline Rush can give the Claymore a devastating punch in the hands of a Soldier.
  • For Grunt it may be a better idea to use the M-22 Eviscerator or Geth Plasma Shotgun over the M-300 because of their superior damage at longer ranges. Squad members tend to shoot shotguns without taking range into account, and tend to shoot more often with weapons that possess a larger clip and higher rate of fire than weapons with a lower fire rate and clip size.

Mass Effect 3[]


The Claymore used to be a hard-hitting but poor-selling shotgun due to kickback problems snapping the arms of anyone but krogan firing the weapon. After a rehaul of its kinetic dampening system, the Claymore is being rolled out again. As a way to lure back customers, the gun's manufacturer has lowered the shotgun's selling price without skimping on its stopping-power.



The M-300 Claymore can be found during the Attican Traverse: Krogan Team, inside the first building. It is also purchasable from Cipritine Armory post-mission if it was missed.


Weapons are randomly rewarded through purchases of item packs. The M-300 Claymore is categorized as rare and requires no multiplayer expansion packs.

Player Notes[]

  • The Claymore is a single-shot shotgun whose standout feature is possessing the most damaging shot of any weapon in the game, even beating out the Javelin.
    • However, being a relatively standard shotgun in other regards, a Claymore shot's damage is divided amongst 8 pellets that fire in an X-shaped spread pattern that widens considerably with firing distance, quickly diluting effectiveness past point-blank range, and making it hard to concentrate damage on enemy heads or weak points.
    • Firing multiple pellets makes the Claymore lose more damage by default to enemy armor protections, but lose very little damage to enemy shield gates, especially on higher difficulties.
  • Despite its impressively damaging shot, the Claymore lacks comparative advantages in almost every other area, which can make it much less attractive than alternatives:
    • The Claymore is one of the heaviest weapons, weighing as much as the N7 Crusader and Black Widow, and lacking the multiple shots, long range effectiveness, or baseline shot penetration those weapons possess.
    • Firing only one shot before having to reload is very unforgiving and puts a premium on consistently landing one-shot kills to make the weapon worth it. Compared with the far lighter AT-12 Raider or M-11 Wraith which both pack a heavy punch while having an extra shot in the magazine to work with, and most classes would not find the Claymore's severe drag on power recharge times worth the tradeoff.
    • The Reegar Carbine can also deal extreme damage in a short time, and it deals heavy bonus damage to shields and barriers. While it suffers from a lack of spare thermal clip capacity, so does the Claymore.
    • The Venom Shotgun's charged shots can also deal massive damage, with the added bonus of being able to hit multiple opponents per shot.
    • Many other non-shotgun weapons can deal enough damage to cause one-shot kills, such as sniper rifles, the Executioner Pistol, or the Arc Pistol. Most of these options are either lighter, have far greater range, or both.
  • If it is modded with the Shotgun Smart Choke, reload cancelling is used efficiently to improve firing rate, and one-shot kills are reliably achieved on infantry targets, the Claymore can still be an effective weapon.
  • Several powers can greatly improve the Claymore's performance:
    • The immobilization of foot soldiers provided by Stasis guarantees the Claymore's single shot will be on target. Stasis also works in tandem with the biotic damage enhancement from Warp Ammo/Warp Rounds.
    • The instant reload of Adrenaline Rush can effectively give the Claymore an extra shot to work with; in single-player, the time slowdown also makes it easier to land the shot.
    • Tactical Cloak's damage boost helps make sure the Claymore's shots are fatal, and the stealth allows players to safely get close to targets for maximum damage.
    • Overload or Energy Drain strips shields and barriers and usually stuns foot soldiers, making it easy to finish them off.


  • The M-300 Claymore is likely named after the two-handed Scottish sword.
  • While the M-300 is described as being usable only by krogan in Mass Effect 2, members of other races are shown using it, including the turian Command Bodyguard, asari Captain Enyala and Commander Shepard (if picked up).
  • The Mass Effect 3 M-300 Claymore model is much smaller than the one used in Mass Effect 2.
  • In Mass Effect 3, the weapon is depicted as having a grey coloured body in the menus. In-game and during modification, however, it is depicted as being green by default. This colour of this part will be changed if the Smart Choke modification is attached.
  • On the side of the weapon, the M-300 name is backwards as "300-M" which resembles the word "BOOM."