I would love to see a AirPoweredDartGun here is what i used this ver. uses a scope in 16.2 stable it may need some work haven't tried to use it on 16.4 also i have mods for pure colors of most cloths shirts pants shorts hats coats blue green red black yellow white and a black trench coat mod if you are interested its mainly just changing the color numbers but some items were not in the game so i made a script for them
 
<item id="1604" name="AirPoweredDartGun">
   <property name="Meshfile" value="Items/Weapons/Ranged/SawedOffPumpShotgun/PumpShotgunPrefab"/>   
   <property name="Material" value="metal"/>
   <property name="CustomIcon" value="airPoweredDartGun" />   
   <property name="RepairTools" value="Co2Refill"/>
   <property name="HoldType" value="5"/>
   <property name="DegradationBreaksAfter" value="false"/>
   <property name="SoundJammed" value="weapon_jam"/>
   <property name="Attachments" value="flashlight02"/>
   <property name="CrosshairOnAim" value="false"/> <!-- aimTest -->
   <property name="CrosshairUpAfterShot" value="true"/> <!-- aimTest -->
   <property name="Sound_Sight_In" value="rifle_sight_in"/>
   <property name="Sound_Sight_Out" value="rifle_sight_out"/>
   <property class="Parts">
      <property name="Stock" value="partsAirPoweredDartGun_stockShort"/>
      <property name="Receiver" value="partsAirPoweredDartGun_cylinder"/>
      <property name="Pump" value="partsAirPoweredDartGun_parts"/>
      <property name="Barrel" value="partsAirPoweredDartGun_barrelShort"/>
   </property>
   <property class="Action0"> <!-- AttackAction -->
      <property name="Class" value="Launcher"/>
      <property name="Hitmask_override" value="Arrow"/>
      <property name="Delay" value="0.7"/>
      <property name="Crosshair_min_distance" value="23"/> <!-- 23 -->
      <property name="Crosshair_max_distance" value="28"/> <!-- 28 -->
      <property name="Magazine_size" value="6"/>
      <property name="Magazine_items" value="steelDart,pyroTipDart,poisonTipDart"/>
      <property name="Magazine_item_ray_counts" value="8, 1"/>
      <property name="Magazine_item_ray_spreads" value="0.835,0.605"/> <!-- .835 / .605 -->
      <property name="Reload_time" value=".6"/>
      <property name="Bullet_icon" value="uzi"/>
      <property name="Sound_start" value="nailgun_fire"/>
      <property name="Sound_repeat" value=""/>
      <property name="Sound_end" value=""/>
      <property name="Sound_empty" value="weapon_empty"/>
      <property name="Sound_reload" value="shotgun_reload"/>
      <property name="Particles_muzzle_fire" value="nailgunfire"/>
      <property name="Particles_muzzle_smoke" value="nozzlesmoke"/>
      <property name="DamageBonus.head" value="3"/>
      <property name="DamageBonus.glass" value="1"/>
      <property name="DamageBonus.wood" value="2"/>
      <property name="DamageBonus.earth" value=".2"/>
      <property name="Buff" value="shotgunWound"/>
      <property name="Buff_chance" value="1.0"/>
   </property>
      <property class="Action1"> <!-- UseAction -->
      <property name="Class" value="Zoom"/>      
      <property name="Zoom_overlay" value="Items/Weapons/HUD/sniper_zoom_overlay"/>
      <property name="Zoom_max_out" value="40"/>
      <property name="Zoom_max_in" value="15"/>
   </property>
   <property name="LightSource" value="lightSource"/> <!-- Start: Needed for the attachment flashlight -->
   <property name="ActivateObject" value="Attachments/flashlight/lightSource"/>
   <property name="AttachmentFlashlight" value="flashlight02"/> <!-- End: Needed for the attachment flashlight -->
   <property name="Group" value="Ammo/Weapons"/>
   <property name="ActionSkillGroup" value="Archery"/>
   <property name="CraftingSkillGroup" value="craftSkillWeapons"/>
   <property name="RepairExpMultiplier" value="10.8"/>
   <property name="PickupJournalEntry" value="alternateAmmoTip"/>
   <property name="LightValue" value="0.45"/>
</item>
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you will have to change the custom parts and icon to prefabs and the ammo type to the game darts unless you like the poison and pyro tips and so on
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<item id="1605" name="Co2Refill">
   <property name="Meshfile" value="Items/Misc/sackPrefab" />
   <property name="DropMeshfile" value="Items/Misc/sack_droppedPrefab" />
   <property name="CustomIcon" value="Co2Refill" />   
   <property name="Material" value="metal" />
   <property name="HoldType" value="45" />
   <property name="Stacknumber" value="50" /> <!-- STK repairKit -->
   <property name="EconomicValue" value="186" />
   <property name="RepairTime" value="2" />
   <property name="RepairAmount" value="2000" />
   <property name="Group" value="Resources,Ammo/Weapons" />
   <property name="CraftingSkillGroup" value="craftSkillScience"/>
</item>
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you will have to change the customIcon
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<item id="1699" name="poisonTipDart">
   <property name="Extends" value="ironArrow" param1="HandMeshfile"/>
   <property name="CustomIcon" value="poisonDart"/>   
   <property name="Meshfile" value="Entities/Electrical/steel_dartPrefab"/>
   <property name="DropMeshfile" value="Items/Misc/sack_droppedPrefab"/>
   <property name="Stacknumber" value="500"/> <!-- STK ammo -->
   <property name="EconomicValue" value="54"/>
   <property name="EconomicBundleSize" value="100"/>
   <property class="Action1">
      <property name="Explosion.ParticleIndex" value="1"/> <!-- no expl. -->
      <property name="Velocity" value="95"/>
      <property name="Gravity" value="-4"/>
      <property name="LifeTime" value="2"/>
      <property name="Explosion.BlockDamage" value="10"/>
      <property name="Explosion.EntityDamage" value="10"/>
      <property name="Explosion.ParticleIndex" value="7"/>
      <property name="Explosion.RadiusBlocks" value="1"/>
      <property name="Explosion.RadiusEntities" value="1"/>
      <property name="Explosion.DamageBonus.stone" value="0.3"/>
      <property name="Explosion.DamageBonus.metal" value="0.1"/>
      <property name="Explosion.DamageBonus.earth" value="0"/> <!-- should work? -->
      <property name="Explosion.DamageBonus.wood" value="0.5"/>
      <property name="Explosion.DamageBonus.water" value="0"/>
   </property>
   <property class="Attributes">
      <property name="EntityDamage" value="22,45"/>
      <property name="BlockDamage" value="6,18"/>
      <property name="ApplyBuff" value="0.4,0.4" param1="infection3"/>
   </property>
   <property name="CraftingSkillGroup" value="craftSkillWeapons"/>
</item>

<item id="1700" name="pyroTipDart">
   <property name="Extends" value="ironArrow" param1="HandMeshfile"/>
   <property name="CustomIcon" value="pyroDart"/>   
   <property name="Meshfile" value="Entities/Electrical/steel_dartPrefab"/>
   <property name="DropMeshfile" value="Items/Misc/sack_droppedPrefab"/>
   <property name="Stacknumber" value="500"/> <!-- STK ammo -->
   <property name="EconomicValue" value="54"/>
   <property name="EconomicBundleSize" value="100"/>
   <property class="Action1">
      <property name="Explosion.ParticleIndex" value="1"/> <!-- no expl. -->
      <property name="Velocity" value="95"/>
      <property name="Gravity" value="-4"/>
      <property name="LifeTime" value="2"/>
      <property name="Explosion.BlockDamage" value="10"/>
      <property name="Explosion.EntityDamage" value="10"/>
      <property name="Explosion.ParticleIndex" value="0"/>
      <property name="Explosion.RadiusBlocks" value="2"/>
      <property name="Explosion.RadiusEntities" value="1"/>
      <property name="Explosion.DamageBonus.stone" value="0.3"/>
      <property name="Explosion.DamageBonus.metal" value="0.1"/>
      <property name="Explosion.DamageBonus.earth" value="0"/> <!-- should work? -->
      <property name="Explosion.DamageBonus.wood" value="0.5"/>
      <property name="Explosion.DamageBonus.water" value="0"/>
   </property>
   <property class="Attributes">
      <property name="EntityDamage" value="22,45"/>
      <property name="BlockDamage" value="6,18"/>
      <property name="ApplyBuff" value="0.4,0.4" param1="burning"/>
   </property>
   <property name="CraftingSkillGroup" value="craftSkillWeapons"/>
</item>
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you will have to change the customIcon