diff --git a/OpenRA.Game/Traits/TraitsInterfaces.cs b/OpenRA.Game/Traits/TraitsInterfaces.cs
index 6e2278eb8b..96d4a0a8c5 100644
--- a/OpenRA.Game/Traits/TraitsInterfaces.cs
+++ b/OpenRA.Game/Traits/TraitsInterfaces.cs
@@ -299,8 +299,6 @@ namespace OpenRA.Traits
 	public interface INotifyBecomingIdle { void OnBecomingIdle(Actor self); }
 	public interface INotifyIdle { void TickIdle(Actor self); }
 
-	public interface IBlocksProjectilesInfo : ITraitInfo { }
-	public interface IBlocksProjectiles { }
 	public interface IRenderInfantrySequenceModifier
 	{
 		bool IsModifyingSequence { get; }
diff --git a/OpenRA.Mods.Common/Effects/Bullet.cs b/OpenRA.Mods.Common/Effects/Bullet.cs
index 4adc33154f..aa8a3be3a3 100644
--- a/OpenRA.Mods.Common/Effects/Bullet.cs
+++ b/OpenRA.Mods.Common/Effects/Bullet.cs
@@ -16,6 +16,7 @@ using OpenRA.Effects;
 using OpenRA.GameRules;
 using OpenRA.Graphics;
 using OpenRA.Mods.Common.Graphics;
+using OpenRA.Mods.Common.Traits;
 using OpenRA.Traits;
 
 namespace OpenRA.Mods.Common.Effects
@@ -171,7 +172,7 @@ namespace OpenRA.Mods.Common.Effects
 
 			var shouldExplode = height.Length <= 0 // Hit the ground
 				|| ticks++ >= length // Flight length reached/exceeded
-				|| (info.Blockable && world.ActorMap.GetUnitsAt(cell).Any(a => a.Info.HasTraitInfo<IBlocksProjectilesInfo>())); // Hit a wall or other blocking obstacle
+				|| BlockedByActor(world, pos); // Hit a wall or other blocking obstacle
 
 			if (shouldExplode)
 				Explode(world);
@@ -211,5 +212,11 @@ namespace OpenRA.Mods.Common.Effects
 
 			args.Weapon.Impact(Target.FromPos(pos), args.SourceActor, args.DamageModifiers);
 		}
+
+		bool BlockedByActor(World world, WPos pos)
+		{
+			return info.Blockable && world.ActorMap.GetUnitsAt(world.Map.CellContaining(pos))
+					.Any(a => a.TraitsImplementing<BlocksProjectiles>().Any(Exts.IsTraitEnabled));
+		}
 	}
 }
diff --git a/OpenRA.Mods.Common/Effects/Missile.cs b/OpenRA.Mods.Common/Effects/Missile.cs
index 8740be76d1..1695636492 100644
--- a/OpenRA.Mods.Common/Effects/Missile.cs
+++ b/OpenRA.Mods.Common/Effects/Missile.cs
@@ -201,7 +201,7 @@ namespace OpenRA.Mods.Common.Effects
 			var shouldExplode = (pos.Z < 0) // Hit the ground
 				|| (dist.LengthSquared < info.CloseEnough.LengthSquared) // Within range
 				|| (info.RangeLimit != 0 && ticks > info.RangeLimit) // Ran out of fuel
-				|| (info.Blockable && world.ActorMap.GetUnitsAt(cell).Any(a => a.Info.HasTraitInfo<IBlocksProjectilesInfo>())) // Hit a wall or other blocking obstacle
+				|| BlockedByActor(world, pos) // Hit a wall or other blocking obstacle
 				|| !world.Map.Contains(cell) // This also avoids an IndexOutOfRangeException in GetTerrainInfo below.
 				|| (!string.IsNullOrEmpty(info.BoundToTerrainType) && world.Map.GetTerrainInfo(cell).Type != info.BoundToTerrainType); // Hit incompatible terrain
 
@@ -223,6 +223,12 @@ namespace OpenRA.Mods.Common.Effects
 			args.Weapon.Impact(Target.FromPos(pos), args.SourceActor, args.DamageModifiers);
 		}
 
+		bool BlockedByActor(World world, WPos pos)
+		{
+			return info.Blockable && world.ActorMap.GetUnitsAt(world.Map.CellContaining(pos))
+					.Any(a => a.TraitsImplementing<BlocksProjectiles>().Any(Exts.IsTraitEnabled));
+		}
+
 		public IEnumerable<IRenderable> Render(WorldRenderer wr)
 		{
 			if (info.ContrailLength > 0)
diff --git a/OpenRA.Mods.Common/Traits/BlocksProjectiles.cs b/OpenRA.Mods.Common/Traits/BlocksProjectiles.cs
index c41398abd6..ac495d3179 100644
--- a/OpenRA.Mods.Common/Traits/BlocksProjectiles.cs
+++ b/OpenRA.Mods.Common/Traits/BlocksProjectiles.cs
@@ -15,6 +15,14 @@ namespace OpenRA.Mods.Common.Traits
 {
 	// TODO: Add functionality like a customizable Height that is compared to projectile altitude
 	[Desc("This actor blocks bullets and missiles with 'Blockable' property.")]
-	public class BlocksProjectilesInfo : TraitInfo<BlocksProjectiles>, IBlocksProjectilesInfo { }
-	public class BlocksProjectiles : IBlocksProjectiles { }
+	public class BlocksProjectilesInfo : UpgradableTraitInfo
+	{
+		public override object Create(ActorInitializer init) { return new BlocksProjectiles(init.Self, this); }
+	}
+
+	public class BlocksProjectiles : UpgradableTrait<BlocksProjectilesInfo>
+	{
+		public BlocksProjectiles(Actor self, BlocksProjectilesInfo info)
+			: base(info) { }
+	}
 }