Mecha weapons can be "retrieved" inside as a move action, in which case they cannot be used, which is useful both for showing peaceful intentions, or using Plain History maneuvers. Making them useable again is another move action. When you exit a mecha, you can choose to leave its weapons retrieved inside or not.
Mecha weapons can be disarmed, representing the weapon being ripped off its supports. Built-in weapons gain a +4 bonus against disarm attempts. A mecha who had a weapon disarmed can pick it up and perform improvised repairs to make it work again as a move action that provokes attacks of opportunity. Each weapon is specially adapted to each mecha, even generic arsenal ones, and thus it's impossible to pick up and use disarmed weapons from other mechas during combat.
Unless otherwise noticed reloading a weapon with ammo is a fullround action.
Brutal:This ranged weapons can always use Str for to hit rolls.
Finesse:This melee weapons can always use Dex for to hit rolls instead of Str. If the pilot has the weapon finesse feat, he can use Dex for damage rolls instead of Str.
Power: attacks ignore half the target's Natural armor, Armor and Shield bonus to AC, rounded up.
Rending: ignores half the target's DR, rounded up.
Heavy: weapon takes a fullround action to use. Can not make iteratives, but you can ready up an attack with an heavy weapon as a fullround action. If any ability would allow you to full attack with a weapon after movement, then it can be used to perform one attack with this weapon. Any ability that would allow you to use a weapon and takes less than a fullround action requires a fullround action to use with a Heavy weapon. If you cannot perform a fullround action at the time you wish to use that maneuver or ability, you may not use a Heavy Weapon with it. A Heavy weapon may not be used as part of the type of Full Attack that uses more than one of the mecha's weapons, as it already requires a fullround action to use. Those weapons add twice Str/Dex modifier to damage rolls instead of just once and gain +10 to resist Disarm rolls if ranged or +20 if melee. If a weapon has somehow the Heavy and Defensive properties simultaneously, then only the Heavy property applies.
Twin-linked:if you have two weapons of the same kind with this property you can attack with both as a standard action whitout penalties or at the end of a charge (if they're melee weapons in the case of a charge). If you perform the full attack action with them, instead of your regular routine you can fire each weapon once for each regular attack you would get with a single weapon. A set of weapons with both the Heavy and Twin-Linked property can both be fired as a single fullround action, all the other Heavy restrictions apply. If you use a Spirit that would benefit only your next attack like Strike or Valor, you may use a pair of Twin-linked weapons and both attacks gain the Spirit's benefit.
X-linked: as twin-linked, except it applies to a set of X weapons, however those weapons cannot benefit from any ability that ignores any amount of DR/hardness.
Defensive: you can fire this weapon as an Immediate action. A pair of Defensive Twin-Linked weapons may be fired as an Immediate action. If you're targeted by a weapon with "Missile" in their name, you may attempt to stop it by attacking it with your Defensive weapon. Make opposed attack rolls, and if you succeed the missile is stopped.
Area():Instead of a normal shot, you may make the weapon fire in an area. The type of area is mentioned in (), so for example Area (line 30 wide 5) means it can affect a line 30 mu long and 5 mu wide. Area (Explosive X) means it affects a sphere of radius X mu at the point of impact, can only be used up to two range increments. If there is no length/width/radius they default to the following.
-Line has the width of your mecha and the same length as the first range increment of the weapon (or twice width and length for Heavy weapons).
-Cone has half the length as the first range increment of the weapon (or same length as first range increment for Heavy weapons).
-Explosive radius equal as 1/4 the first range increment of the weapon (or 1/2 first range increment for Heavy weapon)
If there is no (), defaults to line area.
Roll to hit against all targets inside the area. If you target an oponent bigger than you with this, the area needs to reach the middle of their position.
If this appears in a melee weapon, when you would make a normal attack, you can move in a straight line up to half your base speed, ignoring any opponents in your way for purposes of movement, without causing attacks of opportunity. Any buffs to speed increase the range after the base speed is multiplied. Roll to hit against all opponents you passed through. If your movement would cost EN or other resources, you must pay for it as normal. If an opponent is bigger than you, you need to pass through the middle of their position to affect them with this.
Either way if a weapon somehow has both the Area and Defensive properties, only one can be active at a time.
Pinning: Creatures dealt damage by this weapon have their movement speeds halved for 1 round, with multiple hits stacking to a minimum speed of 5 mu. A Heavy weapon with Pinning reduces movement speeds to 1/4.
Concussive: Creatures dealt damage by this weapon lose half their Dex and Dodge bonus to AC and Reflex saves for 1 round. Multiple hits on the same round don't stack. A Heavy weapon with Concussive also inflicts a -4 penalty on Fort and Will saves on targets damaged.
Disarming: If you deal damage with this weapon, you can attempt a Disarm as a free action on the target without provoking attacks of opportunity nor needing to make a new attack roll, even if at range. You may instead try to remove a random accessory of the enemy, in which case their defensive roll is made with a weapon of their choice. However you cannot try to pick up the weapon of your enemy if you succeed and have a free hand. A Heavy weapon grants a +6 bonus on the Disarm roll.
Pushing: If you deal damage with this weapon, you can attempt a Bullrush as a free action on the target without provoking attacks of opportunity nor needing to move inside the target's space, even if at range. A Heavy weapon grants a +6 bonus on the Bullrush roll.
Downfall: If you deal damage with this weapon, you can attempt a Trip as a free action on the target without provoking attacks of opportunity nor needing to make a new attack roll, even if at range. If you hit a flying enemy, they instead fall 5 mu for each 5 damage taken. A Heavy weapon grants a +6 bonus on the Trip roll.
Grabbing: If you deal damage with this weapon, you can attempt a Grapple as a free action without provoking attacks of opportunity nor needing to make a new attack roll. You can choose to maintain the grapple with this weapon only, in which case you can't use it while the grapple lasts, but you don't count as grappling your target. A Heavy weapon grants a +6 bonus on the Grapple roll.
Volatile: Whenever the mecha suffers damage or rolls a natural 20 on an attack roll with this weapon, there's a 50% chance this weapon is rendered useless until the mecha can swap their arsenal. If a mecha is equipped with multiple Volatile weapons, no more than 1 may explode per round.
Hybrid: A Hybrid weapon has two statlines, which can be changed between as an Immediate action. Any bonus/penalty that affect a weapon benefit both versions of the Hybrid weapon if valid (so for example a melee only bonus would not affect a ranged version of an Hybrid weapon).
BOW: Ballistic Overdive Wire, a revolutionary new system for ranged combat. Double this weapon's base damage die if the target is not standing on a solid inanimate object at least four size categories bigger than themselves. In addition you can "charge up" this weapon as a move action 1/round, in which case also double its base damage die for its next shot. You can charge for up for to 3 rounds after which you must release or the weapon breaks. If you move in any way while charging, even a 5-ft step or teleport or similar, the the charge up is lost.