diff --git a/Defs/Ammo/Shell/81mmMortar.xml b/Defs/Ammo/Shell/81mmMortar.xml
index 49b31aebfb..d4918a97f5 100644
--- a/Defs/Ammo/Shell/81mmMortar.xml
+++ b/Defs/Ammo/Shell/81mmMortar.xml
@@ -129,6 +129,7 @@
 		</statBases>
 		<ammoClass>FoamFuel</ammoClass>
 		<detonateProjectile>Bullet_81mmMortarShell_Firefoam</detonateProjectile>
+		<spawnAsSiegeAmmo>false</spawnAsSiegeAmmo>
 	</ThingDef>
 
 	<ThingDef Class="CombatExtended.AmmoDef" ParentName="81mmMortarShellBaseCraftableBase">
@@ -145,6 +146,7 @@
 		</statBases>
 		<ammoClass>Smoke</ammoClass>
 		<detonateProjectile>Bullet_81mmMortarShell_Smoke</detonateProjectile>
+		<spawnAsSiegeAmmo>false</spawnAsSiegeAmmo>
 	</ThingDef>
 
 	<ThingDef Class="CombatExtended.AmmoDef" ParentName="81mmMortarShellBase">
diff --git a/ModPatches/BiologicalWarfare/Patches/Patches.xml b/ModPatches/BiologicalWarfare/Patches/Patches.xml
index eb1f4d4ec8..8f9e2e5e0f 100644
--- a/ModPatches/BiologicalWarfare/Patches/Patches.xml
+++ b/ModPatches/BiologicalWarfare/Patches/Patches.xml
@@ -289,4 +289,5 @@
 			defName="USH_SleepingSicknessGrenadeLauncher" or
 			defName="USH_SleepingSicknessGrenadeBullet"]</xpath>
 	</Operation>
+	
 </Patch>
\ No newline at end of file
diff --git a/Source/CombatExtended/CombatExtended/Defs/AmmoDef.cs b/Source/CombatExtended/CombatExtended/Defs/AmmoDef.cs
index 961404e3ac..351f7c187f 100644
--- a/Source/CombatExtended/CombatExtended/Defs/AmmoDef.cs
+++ b/Source/CombatExtended/CombatExtended/Defs/AmmoDef.cs
@@ -23,6 +23,7 @@ public class AmmoDef : ThingDef
 
         // mortar ammo should still availabe when the ammo system is off        
         public bool isMortarAmmo = false;
+        public bool spawnAsSiegeAmmo = true;
 
         public int ammoCount = 1;
         public ThingDef partialUnloadAmmoDef = null;
diff --git a/Source/CombatExtended/Harmony/Harmony_LordToil_Siege.cs b/Source/CombatExtended/Harmony/Harmony_LordToil_Siege.cs
index ebd984e9dd..7200056022 100644
--- a/Source/CombatExtended/Harmony/Harmony_LordToil_Siege.cs
+++ b/Source/CombatExtended/Harmony/Harmony_LordToil_Siege.cs
@@ -1,5 +1,7 @@
 using System.Collections.Generic;
+using System.Linq;
 using System.Reflection;
+using System.Reflection.Emit;
 using HarmonyLib;
 using RimWorld;
 using Verse;
@@ -11,8 +13,61 @@ internal static class Harmony_LordToil_Siege
     {
         internal static IEnumerable<CodeInstruction> Transpiler(IEnumerable<CodeInstruction> instructions)
         {
-            return instructions.MethodReplacer(typeof(ThingDef).GetMethod("get_IsShell"),
-                                               typeof(AmmoUtility).GetMethod(nameof(AmmoUtility.IsShell), BindingFlags.Public | BindingFlags.Static));
+            var codes = new List<CodeInstruction>(instructions);
+            var methodCustomCondition = typeof(Harmony_LordToil_Siege).GetMethod(nameof(CustomCondition), BindingFlags.Static | BindingFlags.Public);
+            var startIndex = -1;
+            var endIndex = -1;
+            MethodInfo targetMethod = AccessTools.Method(typeof(ThingDef), "get_IsShell"); // Start of the if condition
+            FieldInfo targetField = AccessTools.Field(typeof(DamageDef), "harmsHealth"); // End of the if condition
+            for (int i = 0; i < codes.Count; i++)
+            {
+                if (startIndex == -1)
+                {
+                    // Find the start of the if statement
+                    if (codes[i].opcode == OpCodes.Callvirt && codes[i].Calls(targetMethod))
+                    {
+                        startIndex = i - 1; // We want to edit -1 instruction from the call of IsShell
+                    }
+                }
+                else if (codes[i].opcode == OpCodes.Ldfld && codes[i].LoadsField(targetField))
+                {
+                    endIndex = i;
+                }
+            }
+            if (startIndex == -1 || endIndex == -1)
+            {
+                Log.Error("CombatExtended :: Harmony_LordToil_Siege couldn't find code block for patching");
+                return codes; // Don't modify as we couldn't find the original code block
+            }
+            else
+            {
+                codes[startIndex] = new CodeInstruction(OpCodes.Call, methodCustomCondition); // Call the new method for evaluation
+                codes.RemoveRange(startIndex + 1, endIndex - startIndex); // Remove the default code
+                return codes;
+            }
+        }
+
+        public static bool CustomCondition(Thing thing)
+        {
+            // Ensure check is the same here as from CombatExtended.HarmonyCE.Harmony_TurretGunUtility
+            var ammoDef = thing.def as AmmoDef;
+            if (ammoDef == null)
+            {
+                return false;
+            }
+
+            // Ignore all non-shell defs.
+            if (ammoDef == null || !AmmoUtility.IsShell(ammoDef))
+            {
+                return false;
+            }
+
+            // Check if shell is blacklisted
+            if (!ammoDef.spawnAsSiegeAmmo)
+            {
+                return false;
+            }
+            return true;
         }
     }
 }
diff --git a/Source/CombatExtended/Harmony/Harmony_TurretGunUtility.cs b/Source/CombatExtended/Harmony/Harmony_TurretGunUtility.cs
index b48496d9cf..627366c629 100644
--- a/Source/CombatExtended/Harmony/Harmony_TurretGunUtility.cs
+++ b/Source/CombatExtended/Harmony/Harmony_TurretGunUtility.cs
@@ -18,7 +18,8 @@ public static class Harmony_TurretGunUtility
         const string className = "DisplayClass";
         const string methodName = "<TryFindRandomShellDef>";
 
-        public static void Postfix(object __instance, ThingDef x, ref bool __result, bool ___allowEMP, float ___maxMarketValue, bool ___mustHarmHealth)
+        // This should be kept up to date with the check in CombatExtended.HarmonyCE.Harmony_LordToil_Siege
+        public static void Postfix(object __instance, ThingDef x, ref bool __result, bool ___allowEMP, float ___maxMarketValue)
         {
             // Ignore already true results.
             if (__result)
@@ -60,8 +61,8 @@ public static void Postfix(object __instance, ThingDef x, ref bool __result, boo
                 return;
             }
 
-            // Check if shell harms health.
-            if (___mustHarmHealth && explosiveDamageDef != null && !explosiveDamageDef.harmsHealth && projectileDamageDef != null && !projectileDamageDef.harmsHealth)
+            // Check if blacklisted
+            if (!ammoDef.spawnAsSiegeAmmo)
             {
                 return;
             }