diff --git a/src/actor.h b/src/actor.h
index 4f37dcf98f..d3a6d94aad 100644
--- a/src/actor.h
+++ b/src/actor.h
@@ -1259,7 +1259,6 @@ public:
 	void LinkToWorld (FLinkContext *ctx, bool spawningmapthing=false, sector_t *sector = NULL);
 	void UnlinkFromWorld(FLinkContext *ctx);
 	void AdjustFloorClip ();
-	bool InStateSequence(FState * newstate, FState * basestate);
 	bool IsMapActor();
 	int GetTics(FState * newstate);
 	bool SetState (FState *newstate, bool nofunction=false);
diff --git a/src/p_mobj.cpp b/src/p_mobj.cpp
index 740bcb18ab..e26465e99c 100644
--- a/src/p_mobj.cpp
+++ b/src/p_mobj.cpp
@@ -425,7 +425,7 @@ AActor &AActor::operator= (const AActor &other)
 //
 //==========================================================================
 
-bool AActor::InStateSequence(FState * newstate, FState * basestate)
+static int InStateSequence(FState * newstate, FState * basestate)
 {
 	if (basestate == NULL) return false;
 
@@ -440,12 +440,19 @@ bool AActor::InStateSequence(FState * newstate, FState * basestate)
 	return false;
 }
 
-DEFINE_ACTION_FUNCTION(AActor, InStateSequence)
+DEFINE_ACTION_FUNCTION(AActor, InStateSequence, InStateSequence)
 {
-	PARAM_SELF_PROLOGUE(AActor);
+	PARAM_PROLOGUE;
 	PARAM_POINTER(newstate, FState);
 	PARAM_POINTER(basestate, FState);
-	ACTION_RETURN_BOOL(self->InStateSequence(newstate, basestate));
+	ACTION_RETURN_BOOL(InStateSequence(newstate, basestate));
+}
+
+DEFINE_ACTION_FUNCTION(FState, InStateSequence, InStateSequence)
+{
+	PARAM_SELF_STRUCT_PROLOGUE(FState);
+	PARAM_POINTER(basestate, FState);
+	ACTION_RETURN_BOOL(InStateSequence(self, basestate));
 }
 
 
diff --git a/wadsrc/static/zscript/actor.txt b/wadsrc/static/zscript/actor.txt
index eed1118f4c..6b09698aaa 100644
--- a/wadsrc/static/zscript/actor.txt
+++ b/wadsrc/static/zscript/actor.txt
@@ -680,7 +680,7 @@ class Actor : Thinker native
 	native void FindFloorCeiling(int flags = 0);
 	native double, double GetFriction();
 	native bool, Actor TestMobjZ(bool quick = false);
-	native bool InStateSequence(State newstate, State basestate);
+	native static bool InStateSequence(State newstate, State basestate);
 	
 	bool TryWalk ()
 	{
diff --git a/wadsrc/static/zscript/base.txt b/wadsrc/static/zscript/base.txt
index 449e8aa09d..466529aeac 100644
--- a/wadsrc/static/zscript/base.txt
+++ b/wadsrc/static/zscript/base.txt
@@ -747,6 +747,7 @@ struct State native
 	native int DistanceTo(state other);
 	native bool ValidateSpriteFrame();
 	native TextureID, bool, Vector2 GetSpriteTexture(int rotation, int skin = 0, Vector2 scale = (0,0));
+	native bool InStateSequence(State base);
 }
 
 struct F3DFloor native
diff --git a/wadsrc/static/zscript/inventory/weapons.txt b/wadsrc/static/zscript/inventory/weapons.txt
index 1c2d1d2e92..7eebdf3dc5 100644
--- a/wadsrc/static/zscript/inventory/weapons.txt
+++ b/wadsrc/static/zscript/inventory/weapons.txt
@@ -811,24 +811,32 @@ class Weapon : StateProvider
 		let player = Owner.player;
 		if (SisterWeapon != NULL && bPowered_Up)
 		{
-			if (GetReadyState() != SisterWeapon.GetReadyState())
+			let ready = GetReadyState();
+			if (ready != SisterWeapon.GetReadyState())
 			{
 				if (player.PendingWeapon == NULL ||	player.PendingWeapon == WP_NOCHANGE)
+				{
 					player.PendingWeapon = SisterWeapon;
+				}
+				player.WeaponState |= WF_REFIRESWITCHOK;
 			}
 			else
 			{
 				let psp = player.FindPSprite(PSP_WEAPON);
-				if (psp != null && psp.Caller == player.ReadyWeapon)
+				if (psp != null && psp.Caller == player.ReadyWeapon && psp.CurState.InStateSequence(ready))
 				{
 					// If the weapon changes but the state does not, we have to manually change the PSprite's caller here.
 					psp.Caller = SisterWeapon;
 					player.ReadyWeapon = SisterWeapon;
 				}
-				else
+				else 
 				{
-					// Something went wrong. Initiate a regular weapon change.
-					player.PendingWeapon = SisterWeapon;
+					if (player.PendingWeapon == NULL || player.PendingWeapon == WP_NOCHANGE)
+					{
+						// Something went wrong. Initiate a regular weapon change.
+						player.PendingWeapon = SisterWeapon;
+					}
+					player.WeaponState |= WF_REFIRESWITCHOK;
 				}
 			}
 		}