diff --git a/src/p_acs.cpp b/src/p_acs.cpp
index 4bd7df6a9..4b253efb8 100644
--- a/src/p_acs.cpp
+++ b/src/p_acs.cpp
@@ -112,13 +112,12 @@ FRandom pr_acs ("ACS");
 
 struct CallReturn
 {
-	CallReturn(int pc, ScriptFunction *func, FBehavior *module, SDWORD *locals, bool discard, FString &str)
+	CallReturn(int pc, ScriptFunction *func, FBehavior *module, SDWORD *locals, bool discard)
 		: ReturnFunction(func),
 		  ReturnModule(module),
 		  ReturnLocals(locals),
 		  ReturnAddress(pc),
-		  bDiscardResult(discard),
-		  StringBuilder(str)
+		  bDiscardResult(discard)
 	{}
 
 	ScriptFunction *ReturnFunction;
@@ -126,7 +125,6 @@ struct CallReturn
 	SDWORD *ReturnLocals;
 	int ReturnAddress;
 	int bDiscardResult;
-	FString StringBuilder;
 };
 
 static DLevelScript *P_GetScriptGoing (AActor *who, line_t *where, int num, const ScriptPtr *code, FBehavior *module,
@@ -170,8 +168,8 @@ TArray<FString>
 	ACS_StringsOnTheFly,
 	ACS_StringBuilderStack;
 
-#define STRINGBUILDER_START(Builder) if (*Builder.GetChars() || ACS_StringBuilderStack.Size()) { ACS_StringBuilderStack.Push(Builder); Builder = ""; }
-#define STRINGBUILDER_FINISH(Builder) if (!ACS_StringBuilderStack.Pop(Builder)) Builder = "";
+#define STRINGBUILDER_START(Builder) if (Builder.IsNotEmpty() || ACS_StringBuilderStack.Size()) { ACS_StringBuilderStack.Push(Builder); Builder = ""; }
+#define STRINGBUILDER_FINISH(Builder) if (!ACS_StringBuilderStack.Pop(Builder)) { Builder = ""; }
 
 //============================================================================
 //
@@ -4323,7 +4321,7 @@ int DLevelScript::RunScript ()
 				}
 				sp += i;
 				::new(&Stack[sp]) CallReturn(activeBehavior->PC2Ofs(pc), activeFunction,
-					activeBehavior, mylocals, pcd == PCD_CALLDISCARD, work);
+					activeBehavior, mylocals, pcd == PCD_CALLDISCARD);
 				sp += (sizeof(CallReturn) + sizeof(int) - 1) / sizeof(int);
 				pc = module->Ofs2PC (func->Address);
 				activeFunction = func;
@@ -4362,7 +4360,6 @@ int DLevelScript::RunScript ()
 				{
 					Stack[sp++] = value;
 				}
-				work = ret->StringBuilder;
 				ret->~CallReturn();
 			}
 			break;
@@ -7570,6 +7567,3 @@ void DACSThinker::DumpScriptStatus ()
 		script = script->next;
 	}
 }
-
-#undef STRINGBUILDER_START
-#undef STRINGBUILDER_FINISH