diff --git a/src/p_actionfunctions.cpp b/src/p_actionfunctions.cpp
index b90f656c1..32161ed07 100644
--- a/src/p_actionfunctions.cpp
+++ b/src/p_actionfunctions.cpp
@@ -2270,6 +2270,7 @@ DEFINE_ACTION_FUNCTION(AActor, A_CustomRailgun)
 	PARAM_FLOAT_DEF	(spawnofs_z)		
 	PARAM_INT_DEF	(SpiralOffset)		
 	PARAM_INT_DEF	(limit)				
+	PARAM_FLOAT_DEF	(veleffect)
 
 	if (range == 0) range = 8192.;
 	if (sparsity == 0) sparsity = 1;
@@ -2308,7 +2309,7 @@ DEFINE_ACTION_FUNCTION(AActor, A_CustomRailgun)
 	// Let the aim trail behind the player
 	if (aim)
 	{
-		saved_angle = self->Angles.Yaw = self->AngleTo(self->target, -self->target->Vel.X * 3, -self->target->Vel.Y * 3);
+		saved_angle = self->Angles.Yaw = self->AngleTo(self->target, -self->target->Vel.X * veleffect, -self->target->Vel.Y * veleffect);
 
 		if (aim == CRF_AIMDIRECT)
 		{
@@ -2318,7 +2319,7 @@ DEFINE_ACTION_FUNCTION(AActor, A_CustomRailgun)
 				spawnofs_xy * self->Angles.Yaw.Cos(),
 				spawnofs_xy * self->Angles.Yaw.Sin()));
 			spawnofs_xy = 0;
-			self->Angles.Yaw = self->AngleTo(self->target,- self->target->Vel.X * 3, -self->target->Vel.Y * 3);
+			self->Angles.Yaw = self->AngleTo(self->target,- self->target->Vel.X * veleffect, -self->target->Vel.Y * veleffect);
 		}
 
 		if (self->target->flags & MF_SHADOW)
diff --git a/wadsrc/static/zscript/actor.txt b/wadsrc/static/zscript/actor.txt
index f2bff047f..4635105cb 100644
--- a/wadsrc/static/zscript/actor.txt
+++ b/wadsrc/static/zscript/actor.txt
@@ -702,7 +702,7 @@ class Actor : Thinker native
 	native action state A_Jump(int chance, statelabel label, ...);
 	native void A_SpawnProjectile(class<Actor> missiletype, double spawnheight = 32, double spawnofs_xy = 0, double angle = 0, int flags = 0, double pitch = 0, int ptr = AAPTR_TARGET);
 	native void A_CustomBulletAttack(double spread_xy, double spread_z, int numbullets, int damageperbullet, class<Actor> pufftype = "BulletPuff", double range = 0, int flags = 0, int ptr = AAPTR_TARGET, class<Actor> missile = null, double Spawnheight = 32, double Spawnofs_xy = 0);
-	native void A_CustomRailgun(int damage, int spawnofs_xy = 0, color color1 = 0, color color2 = 0, int flags = 0, int aim = 0, double maxdiff = 0, class<Actor> pufftype = "BulletPuff", double spread_xy = 0, double spread_z = 0, double range = 0, int duration = 0, double sparsity = 1.0, double driftspeed = 1.0, class<Actor> spawnclass = null, double spawnofs_z = 0, int spiraloffset = 270, int limit = 0);
+	native void A_CustomRailgun(int damage, int spawnofs_xy = 0, color color1 = 0, color color2 = 0, int flags = 0, int aim = 0, double maxdiff = 0, class<Actor> pufftype = "BulletPuff", double spread_xy = 0, double spread_z = 0, double range = 0, int duration = 0, double sparsity = 1.0, double driftspeed = 1.0, class<Actor> spawnclass = null, double spawnofs_z = 0, int spiraloffset = 270, int limit = 0, double veleffect = 3);
 	native bool A_SetInventory(class<Inventory> itemtype, int amount, int ptr = AAPTR_DEFAULT, bool beyondMax = false);
 	native bool A_GiveInventory(class<Inventory> itemtype, int amount = 0, int giveto = AAPTR_DEFAULT);
 	native bool A_TakeInventory(class<Inventory> itemtype, int amount = 0, int flags = 0, int giveto = AAPTR_DEFAULT);