diff --git a/Libraries/SPTarkov.Server.Core/Exceptions/Items/ItemHelperException.cs b/Libraries/SPTarkov.Server.Core/Exceptions/Items/ItemHelperException.cs
new file mode 100644
index 00000000..b0f3b065
--- /dev/null
+++ b/Libraries/SPTarkov.Server.Core/Exceptions/Items/ItemHelperException.cs
@@ -0,0 +1,10 @@
+namespace SPTarkov.Server.Core.Exceptions.Items;
+
+public class ItemHelperException : Exception
+{
+    public ItemHelperException(string message)
+        : base(message) { }
+
+    public ItemHelperException(string message, Exception innerException)
+        : base(message, innerException) { }
+}
diff --git a/Libraries/SPTarkov.Server.Core/Helpers/ItemHelper.cs b/Libraries/SPTarkov.Server.Core/Helpers/ItemHelper.cs
index 4056a842..0344752f 100644
--- a/Libraries/SPTarkov.Server.Core/Helpers/ItemHelper.cs
+++ b/Libraries/SPTarkov.Server.Core/Helpers/ItemHelper.cs
@@ -1,5 +1,6 @@
 using System.Collections.Frozen;
 using SPTarkov.DI.Annotations;
+using SPTarkov.Server.Core.Exceptions.Items;
 using SPTarkov.Server.Core.Extensions;
 using SPTarkov.Server.Core.Models.Common;
 using SPTarkov.Server.Core.Models.Eft.Common;
@@ -128,7 +129,7 @@ public class ItemHelper(
     /// <param name="tpl">Item tpl to find</param>
     /// <param name="slotId">OPTIONAL - slotId of desired item</param>
     /// <returns>Item or null if no item found</returns>
-    public Item GetItemFromPoolByTpl(IEnumerable<Item> itemPool, MongoId tpl, string slotId = "")
+    public Item? GetItemFromPoolByTpl(IEnumerable<Item> itemPool, MongoId tpl, string slotId = "")
     {
         // Filter the pool by slotId if provided
         var filteredPool = string.IsNullOrEmpty(slotId)
@@ -182,7 +183,7 @@ public class ItemHelper(
         Upd itemProperties = new();
 
         // Armors, etc
-        if (itemTemplate.Properties.MaxDurability is not null)
+        if (itemTemplate.Properties?.MaxDurability is not null)
         {
             itemProperties.Repairable = new UpdRepairable
             {
@@ -191,43 +192,34 @@ public class ItemHelper(
             };
         }
 
-        if (itemTemplate.Properties.HasHinge ?? false)
+        if (itemTemplate.Properties?.HasHinge ?? false)
         {
             itemProperties.Togglable = new UpdTogglable { On = true };
         }
 
-        if (itemTemplate.Properties.Foldable ?? false)
+        if (itemTemplate.Properties?.Foldable ?? false)
         {
             itemProperties.Foldable = new UpdFoldable { Folded = false };
         }
 
-        if (itemTemplate.Properties.WeapFireType?.Any() ?? false)
+        if (itemTemplate.Properties?.WeapFireType?.Count == 0)
         {
-            if (itemTemplate.Properties.WeapFireType.Contains("fullauto"))
-            {
-                itemProperties.FireMode = new UpdFireMode { FireMode = "fullauto" };
-            }
-            else
-            {
-                itemProperties.FireMode = new UpdFireMode { FireMode = randomUtil.GetArrayValue(itemTemplate.Properties.WeapFireType) };
-            }
+            itemProperties.FireMode = itemTemplate.Properties.WeapFireType.Contains("fullauto")
+                ? new UpdFireMode { FireMode = "fullauto" }
+                : new UpdFireMode { FireMode = randomUtil.GetArrayValue(itemTemplate.Properties.WeapFireType) };
         }
 
-        if (itemTemplate.Properties.MaxHpResource is not null)
+        if (itemTemplate.Properties?.MaxHpResource is not null)
         {
             itemProperties.MedKit = new UpdMedKit { HpResource = itemTemplate.Properties.MaxHpResource };
         }
 
-        if (itemTemplate.Properties.MaxResource is not null && itemTemplate.Properties.FoodUseTime is not null)
+        if (itemTemplate.Properties?.MaxResource is not null && itemTemplate.Properties.FoodUseTime is not null)
         {
             itemProperties.FoodDrink = new UpdFoodDrink { HpPercent = itemTemplate.Properties.MaxResource };
         }
 
-        if (itemTemplate.Parent == BaseClasses.FLASHLIGHT)
-        {
-            itemProperties.Light = new UpdLight { IsActive = false, SelectedMode = 0 };
-        }
-        else if (itemTemplate.Parent == BaseClasses.TACTICAL_COMBO)
+        if (itemTemplate.Parent == BaseClasses.FLASHLIGHT || itemTemplate.Parent == BaseClasses.TACTICAL_COMBO)
         {
             itemProperties.Light = new UpdLight { IsActive = false, SelectedMode = 0 };
         }
@@ -238,7 +230,7 @@ public class ItemHelper(
         }
 
         // Toggleable face shield
-        if ((itemTemplate.Properties.HasHinge ?? false) && (itemTemplate.Properties.FaceShieldComponent ?? false))
+        if ((itemTemplate.Properties?.HasHinge ?? false) && (itemTemplate.Properties.FaceShieldComponent ?? false))
         {
             itemProperties.Togglable = new UpdTogglable { On = false };
         }
@@ -248,11 +240,17 @@ public class ItemHelper(
 
     /// <summary>
     /// Checks if a tpl is a valid item. Valid meaning that it's an item that can be stored in stash
+    /// <br/><br/>
     /// Valid means:
+    /// <br/>
     /// Not quest item
+    /// <br/>
     /// 'Item' type
+    /// <br/>
     /// Not on the invalid base types array
+    /// <br/>
     /// Price above 0 roubles
+    /// <br/>
     /// </summary>
     /// <param name="tpl">Template id to check</param>
     /// <param name="invalidBaseTypes">OPTIONAL - Base types deemed invalid</param>
@@ -262,6 +260,11 @@ public class ItemHelper(
         var baseTypes = invalidBaseTypes ?? _defaultInvalidBaseTypes;
         var itemDetails = GetItem(tpl);
 
+        if (itemDetails.Value is null)
+        {
+            return false;
+        }
+
         return itemDetails.Key && IsValidItem(itemDetails.Value, baseTypes);
     }
 
@@ -280,7 +283,7 @@ public class ItemHelper(
     {
         var baseTypes = invalidBaseTypes ?? _defaultInvalidBaseTypes;
 
-        return !(item.Properties.QuestItem ?? false)
+        return !(item.Properties?.QuestItem ?? false)
             && string.Equals(item.Type, "Item", StringComparison.OrdinalIgnoreCase)
             && GetItemPrice(item.Id) > 0
             && !itemFilterService.IsItemBlacklisted(item.Id)
@@ -346,7 +349,9 @@ public class ItemHelper(
         var itemTemplate = GetItem(itemTpl);
 
         return itemTemplate.Value?.Properties?.Slots is not null
-            && itemTemplate.Value.Properties.Slots.Any(slot => _removablePlateSlotIds.Contains(slot.Name.ToLowerInvariant()));
+            && itemTemplate.Value.Properties.Slots.Any(slot =>
+                _removablePlateSlotIds.Contains(slot.Name?.ToLowerInvariant() ?? string.Empty)
+            );
     }
 
     /// <summary>
@@ -370,18 +375,13 @@ public class ItemHelper(
         }
 
         // Has no slots
-        if (!(itemDbDetails.Value.Properties.Slots ?? []).Any())
+        if (!(itemDbDetails.Value?.Properties?.Slots ?? []).Any())
         {
             return false;
         }
 
         // Check if item has slots that match soft insert name ids
-        if (itemDbDetails.Value.Properties.Slots.Any(slot => IsSoftInsertId(slot.Name.ToLowerInvariant())))
-        {
-            return true;
-        }
-
-        return false;
+        return itemDbDetails.Value?.Properties?.Slots?.Any(slot => IsSoftInsertId(slot.Name?.ToLowerInvariant() ?? string.Empty)) ?? false;
     }
 
     /// <summary>
@@ -481,7 +481,7 @@ public class ItemHelper(
     ///     Get cloned copy of all item data from items.json
     /// </summary>
     /// <returns>List of TemplateItem objects</returns>
-    public List<TemplateItem> GetItemsClone()
+    public List<TemplateItem>? GetItemsClone()
     {
         return cloner.Clone(databaseService.GetItems().Values.ToList());
     }
@@ -588,7 +588,7 @@ public class ItemHelper(
         if (
             skipArmorItemsWithoutDurability
             && IsOfBaseclass(item.Template, BaseClasses.ARMOR)
-            && itemDetails?.Properties?.MaxDurability == 0
+            && itemDetails.Properties?.MaxDurability == 0
         )
         {
             return -1;
@@ -599,7 +599,7 @@ public class ItemHelper(
             if (item.Upd.MedKit is not null)
             {
                 // Meds
-                result = (item.Upd.MedKit.HpResource ?? 0) / (itemDetails.Properties.MaxHpResource ?? 0);
+                result = (item.Upd.MedKit.HpResource ?? 0) / (itemDetails.Properties?.MaxHpResource ?? 0);
             }
             else if (item.Upd.Repairable is not null)
             {
@@ -607,9 +607,9 @@ public class ItemHelper(
             }
             else if (item.Upd.FoodDrink is not null)
             {
-                result = (item.Upd.FoodDrink.HpPercent ?? 0) / (itemDetails.Properties.MaxResource ?? 0);
+                result = (item.Upd.FoodDrink.HpPercent ?? 0) / (itemDetails.Properties?.MaxResource ?? 0);
             }
-            else if (item.Upd.Key?.NumberOfUsages > 0 && itemDetails.Properties.MaximumNumberOfUsage > 0)
+            else if (item.Upd.Key?.NumberOfUsages > 0 && itemDetails.Properties?.MaximumNumberOfUsage > 0)
             {
                 // keys - keys count upwards, not down like everything else
                 var maxNumOfUsages = itemDetails.Properties.MaximumNumberOfUsage;
@@ -618,11 +618,11 @@ public class ItemHelper(
             else if (item.Upd.Resource?.UnitsConsumed > 0)
             {
                 // E.g. fuel tank
-                result = (item.Upd.Resource.Value ?? 0) / (itemDetails.Properties.MaxResource ?? 0);
+                result = (item.Upd.Resource.Value ?? 0) / (itemDetails.Properties?.MaxResource ?? 0);
             }
             else if (item.Upd.RepairKit is not null)
             {
-                result = (item.Upd.RepairKit.Resource ?? 0) / (itemDetails.Properties.MaxRepairResource ?? 0);
+                result = (item.Upd.RepairKit.Resource ?? 0) / (itemDetails.Properties?.MaxRepairResource ?? 0);
             }
 
             if (result == 0)
@@ -732,7 +732,7 @@ public class ItemHelper(
             return null;
         }
 
-        return item.Properties.StackMaxSize > 1;
+        return item.Properties?.StackMaxSize > 1;
     }
 
     /// <summary>
@@ -742,12 +742,12 @@ public class ItemHelper(
     /// <returns>List of root item + children.</returns>
     public List<Item> SplitStack(Item itemToSplit)
     {
-        if (itemToSplit?.Upd?.StackObjectsCount is null)
+        if (itemToSplit.Upd?.StackObjectsCount is null)
         {
             return [itemToSplit];
         }
 
-        var maxStackSize = GetItem(itemToSplit.Template).Value.Properties.StackMaxSize;
+        var maxStackSize = GetItem(itemToSplit.Template).Value?.Properties?.StackMaxSize;
         var remainingCount = itemToSplit.Upd.StackObjectsCount;
         List<Item> rootAndChildren = [];
 
@@ -755,7 +755,7 @@ public class ItemHelper(
         // return the item as is.
         if (remainingCount <= maxStackSize)
         {
-            rootAndChildren.Add(cloner.Clone(itemToSplit));
+            rootAndChildren.Add(cloner.Clone(itemToSplit)!);
 
             return rootAndChildren;
         }
@@ -765,8 +765,8 @@ public class ItemHelper(
             var amount = Math.Min(remainingCount.Value, maxStackSize ?? 0);
             var newStackClone = cloner.Clone(itemToSplit);
 
-            newStackClone.Id = new MongoId();
-            newStackClone.Upd.StackObjectsCount = amount;
+            newStackClone!.Id = new MongoId();
+            newStackClone.Upd!.StackObjectsCount = amount;
             remainingCount -= amount;
             rootAndChildren.Add(newStackClone);
         }
@@ -788,7 +788,7 @@ public class ItemHelper(
             return [itemWithChildren];
         }
 
-        var maxStackSize = GetItem(originRootItem.Template).Value.Properties.StackMaxSize;
+        var maxStackSize = GetItem(originRootItem.Template).Value?.Properties?.StackMaxSize;
         var remainingCount = originRootItem.Upd.StackObjectsCount;
         List<List<Item>> result = [];
 
@@ -804,11 +804,11 @@ public class ItemHelper(
         while (remainingCount > 0)
         {
             // Clone item and make IDs unique
-            var itemWithChildrenClone = cloner.Clone(itemWithChildren).ReplaceIDs().ToList();
+            var itemWithChildrenClone = cloner.Clone(itemWithChildren)!.ReplaceIDs().ToList();
 
             // Set stack count to new value
             var amount = Math.Min(remainingCount.Value, maxStackSize ?? 0);
-            itemWithChildrenClone[0].Upd.StackObjectsCount = amount;
+            itemWithChildrenClone[0].Upd!.StackObjectsCount = amount;
             remainingCount -= amount;
             result.Add(itemWithChildrenClone);
         }
@@ -824,7 +824,7 @@ public class ItemHelper(
     public List<List<Item>> SplitStackIntoSeparateItems(Item itemToSplit)
     {
         var itemTemplate = GetItem(itemToSplit.Template).Value;
-        var itemMaxStackSize = itemTemplate.Properties.StackMaxSize ?? 1;
+        var itemMaxStackSize = itemTemplate?.Properties?.StackMaxSize ?? 1;
 
         // item already within bounds of stack size, return it
         if (itemToSplit.Upd?.StackObjectsCount <= itemMaxStackSize)
@@ -837,14 +837,14 @@ public class ItemHelper(
 
         // Split items stack into chunks
         List<List<Item>> result = [];
-        var remainingCount = itemToSplit.Upd.StackObjectsCount;
+        var remainingCount = itemToSplit.Upd?.StackObjectsCount;
         while (remainingCount != 0)
         {
             var amount = Math.Min(remainingCount ?? 0, itemMaxStackSize);
-            var newItemClone = cloner.Clone(itemToSplit);
+            var newItemClone = cloner.Clone(itemToSplit)!;
 
             newItemClone.Id = new MongoId();
-            newItemClone.Upd.StackObjectsCount = amount;
+            newItemClone.Upd!.StackObjectsCount = amount;
             remainingCount -= amount;
             result.Add([newItemClone]);
         }
@@ -885,7 +885,7 @@ public class ItemHelper(
     /// </summary>
     /// <param name="itemWithChildren">Item with mods to update.</param>
     /// <param name="newId">New id to add on children of base item.</param>
-    public void ReplaceRootItemID(IEnumerable<Item> itemWithChildren, MongoId newId)
+    public void ReplaceRootItemId(IEnumerable<Item> itemWithChildren, MongoId newId)
     {
         // original id on base item
         var oldId = itemWithChildren.First().Id;
@@ -931,6 +931,11 @@ public class ItemHelper(
             itemIdBlacklist.UnionWith(insuredItems.Select(x => x.ItemId.Value));
         }
 
+        if (inventory.Items is null)
+        {
+            return;
+        }
+
         foreach (var item in inventory.Items)
         {
             if (itemIdBlacklist.Contains(item.Id))
@@ -948,7 +953,7 @@ public class ItemHelper(
             item.Id = newId;
 
             // Find all children of item and update their parent ids to match
-            var childItems = inventory.Items.Where(x => x.ParentId == originalId);
+            var childItems = inventory.Items.Where(x => x.ParentId is not null && x.ParentId == originalId);
             foreach (var childItem in childItems)
             {
                 childItem.ParentId = newId;
@@ -960,7 +965,7 @@ public class ItemHelper(
                 continue;
             }
 
-            // Update quickslot id
+            // Update quick-slot id
             if (inventory.FastPanel.ContainsKey(originalId))
             {
                 inventory.FastPanel[originalId] = newId;
@@ -975,14 +980,8 @@ public class ItemHelper(
     /// <param name="originalItems">Items to adjust the IDs of</param>
     /// <param name="pmcData">Player profile</param>
     /// <param name="insuredItems">Insured items that should not have their IDs replaced</param>
-    /// <param name="fastPanel">Quick slot panel</param>
     /// <returns>Items</returns>
-    public IEnumerable<Item> ReplaceIDs(
-        IEnumerable<Item> originalItems,
-        PmcData? pmcData,
-        IEnumerable<InsuredItem>? insuredItems = null,
-        Dictionary<string, string>? fastPanel = null
-    )
+    public IEnumerable<Item> ReplaceIDs(IEnumerable<Item> originalItems, PmcData? pmcData, IEnumerable<InsuredItem>? insuredItems = null)
     {
         // Blacklist
         var itemIdBlacklist = new HashSet<MongoId>();
@@ -1033,12 +1032,12 @@ public class ItemHelper(
             }
 
             // Also replace in quick slot if the old ID exists.
-            if (pmcData.Inventory.FastPanel is null)
+            if (pmcData?.Inventory?.FastPanel is null)
             {
                 continue;
             }
 
-            // Update quickslot id
+            // Update quick-slot id
             // TODO: i dont think the fast panel key is a mongoid, it should be e.g. "Item4"
             if (pmcData.Inventory.FastPanel.ContainsKey(originalId))
             {
@@ -1184,7 +1183,7 @@ public class ItemHelper(
 
         while (currentItem != null && IsAttachmentAttached(currentItem))
         {
-            currentItem = itemsMap.FirstOrDefault(x => x.Key == currentItem.ParentId).Value;
+            currentItem = itemsMap.FirstOrDefault(kvp => kvp.Key == currentItem.ParentId).Value;
             if (currentItem == null)
             {
                 return null;
@@ -1203,9 +1202,11 @@ public class ItemHelper(
     {
         HashSet<string> check = ["hideout", "main"];
 
+        var slotId = item.SlotId ?? string.Empty;
+
         return !(
-            check.Contains(item.SlotId) // Is root item
-            || _slotsAsStrings.Contains(item.SlotId) // Is root item in equipment slot e.g. `Headwear`
+            check.Contains(slotId) // Is root item
+            || _slotsAsStrings.Contains(slotId) // Is root item in equipment slot e.g. `Headwear`
             || int.TryParse(item.SlotId, out _)
         ); // Has int as slotId, is inside container. e.g. cartridges
     }
@@ -1228,9 +1229,9 @@ public class ItemHelper(
     {
         var currentItem = itemsMap.GetValueOrDefault(itemId);
 
-        while (currentItem is not null && !_slotsAsStrings.Contains(currentItem.SlotId))
+        while (currentItem is not null && !_slotsAsStrings.Contains(currentItem.SlotId ?? string.Empty))
         {
-            currentItem = itemsMap.GetValueOrDefault(currentItem.ParentId);
+            currentItem = itemsMap.GetValueOrDefault(currentItem.ParentId ?? string.Empty);
             if (currentItem is null)
             {
                 return null;
@@ -1246,11 +1247,22 @@ public class ItemHelper(
     /// <param name="items">Item with children</param>
     /// <param name="rootItemId">The base items root id</param>
     /// <returns>ItemSize object (width and height)</returns>
-    public ItemSize GetItemSize(ICollection<Item> items, MongoId rootItemId)
+    public ItemSize? GetItemSize(ICollection<Item> items, MongoId rootItemId)
     {
-        var rootTemplate = GetItem(items.FirstOrDefault(x => x.Id == rootItemId).Template).Value;
-        var width = rootTemplate.Properties.Width;
-        var height = rootTemplate.Properties.Height;
+        var itemTemplate = items.FirstOrDefault(x => x.Id == rootItemId)?.Template;
+        if (itemTemplate is null)
+        {
+            return null;
+        }
+
+        var rootTemplate = GetItem(itemTemplate.Value).Value;
+        if (rootTemplate is null)
+        {
+            return null;
+        }
+
+        var width = rootTemplate.Properties?.Width;
+        var height = rootTemplate.Properties?.Height;
 
         var sizeUp = 0;
         var sizeDown = 0;
@@ -1268,7 +1280,7 @@ public class ItemHelper(
             var itemDbTemplate = GetItem(item.Template).Value;
 
             // Calculating child ExtraSize
-            if (itemDbTemplate.Properties.ExtraSizeForceAdd ?? false)
+            if (itemDbTemplate?.Properties?.ExtraSizeForceAdd ?? false)
             {
                 forcedUp += itemDbTemplate.Properties.ExtraSizeUp.Value;
                 forcedDown += itemDbTemplate.Properties.ExtraSizeDown.Value;
@@ -1277,11 +1289,11 @@ public class ItemHelper(
             }
             else
             {
-                sizeUp = sizeUp < itemDbTemplate.Properties.ExtraSizeUp ? itemDbTemplate.Properties.ExtraSizeUp.Value : sizeUp;
-                sizeDown = sizeDown < itemDbTemplate.Properties.ExtraSizeDown ? itemDbTemplate.Properties.ExtraSizeDown.Value : sizeDown;
-                sizeLeft = sizeLeft < itemDbTemplate.Properties.ExtraSizeLeft ? itemDbTemplate.Properties.ExtraSizeLeft.Value : sizeLeft;
+                sizeUp = sizeUp < itemDbTemplate?.Properties?.ExtraSizeUp ? itemDbTemplate.Properties.ExtraSizeUp.Value : sizeUp;
+                sizeDown = sizeDown < itemDbTemplate?.Properties?.ExtraSizeDown ? itemDbTemplate.Properties.ExtraSizeDown.Value : sizeDown;
+                sizeLeft = sizeLeft < itemDbTemplate?.Properties?.ExtraSizeLeft ? itemDbTemplate.Properties.ExtraSizeLeft.Value : sizeLeft;
                 sizeRight =
-                    sizeRight < itemDbTemplate.Properties.ExtraSizeRight ? itemDbTemplate.Properties.ExtraSizeRight.Value : sizeRight;
+                    sizeRight < itemDbTemplate?.Properties?.ExtraSizeRight ? itemDbTemplate.Properties.ExtraSizeRight.Value : sizeRight;
             }
         }
 
@@ -1316,10 +1328,10 @@ public class ItemHelper(
     /// <param name="ammoBoxDetails">Item template from items db</param>
     public void AddCartridgesToAmmoBox(List<Item> ammoBox, TemplateItem ammoBoxDetails)
     {
-        var ammoBoxMaxCartridgeCount = ammoBoxDetails.Properties.StackSlots.First().MaxCount;
-        var cartridgeTpl = ammoBoxDetails.Properties.StackSlots.First().Props.Filters.First().Filter.FirstOrDefault();
-        var cartridgeDetails = GetItem(cartridgeTpl);
-        var cartridgeMaxStackSize = cartridgeDetails.Value.Properties.StackMaxSize;
+        var ammoBoxMaxCartridgeCount = ammoBoxDetails.Properties?.StackSlots?.First().MaxCount;
+        var cartridgeTpl = ammoBoxDetails.Properties?.StackSlots?.First().Props?.Filters?.First().Filter?.FirstOrDefault();
+        var cartridgeDetails = GetItem(cartridgeTpl.Value);
+        var cartridgeMaxStackSize = cartridgeDetails.Value?.Properties?.StackMaxSize;
 
         // Exit early if ammo already exists in box
         if (ammoBox.Any(item => item.Template.Equals(cartridgeTpl)))
@@ -1339,7 +1351,7 @@ public class ItemHelper(
             var cartridgeCountToAdd = remainingSpace < maxPerStack ? remainingSpace : maxPerStack;
 
             // Add cartridge item into items array
-            var cartridgeItemToAdd = CreateCartridges(ammoBox[0].Id, cartridgeTpl, (int)cartridgeCountToAdd, location);
+            var cartridgeItemToAdd = CreateCartridges(ammoBox[0].Id, cartridgeTpl.Value, (int)cartridgeCountToAdd, location);
 
             // In live no ammo box has the first cartridge item with a location
             if (location == 0)
@@ -1387,11 +1399,14 @@ public class ItemHelper(
     )
     {
         var chosenCaliber = caliber ?? GetRandomValidCaliber(magTemplate);
-
-        // Edge case - Klin pp-9 has a typo in its ammo caliber
-        if (chosenCaliber == "Caliber9x18PMM")
+        switch (chosenCaliber)
         {
-            chosenCaliber = "Caliber9x18PM";
+            case null:
+                throw new ItemHelperException("Chosen caliber is null when trying to fill magazine with random cartridge");
+            // Edge case - Klin pp-9 has a typo in its ammo caliber
+            case "Caliber9x18PMM":
+                chosenCaliber = "Caliber9x18PM";
+                break;
         }
 
         // Chose a randomly weighted cartridge that fits
@@ -1405,7 +1420,7 @@ public class ItemHelper(
         {
             if (logger.IsLogEnabled(LogLevel.Debug))
             {
-                logger.Debug($"Unable to fill item: {magazine.FirstOrDefault().Id} {magTemplate.Name} with cartridges, none found.");
+                logger.Debug($"Unable to fill item: {magazine.FirstOrDefault()?.Id} {magTemplate.Name} with cartridges, none found.");
             }
 
             return;
@@ -1428,8 +1443,8 @@ public class ItemHelper(
         double minSizeMultiplier = 0.25
     )
     {
-        var isUBGL = IsOfBaseclass(magTemplate.Id, BaseClasses.LAUNCHER);
-        if (isUBGL)
+        var isUbgl = IsOfBaseclass(magTemplate.Id, BaseClasses.LAUNCHER);
+        if (isUbgl)
         // UBGL don't have mags
         {
             return;
@@ -1509,8 +1524,13 @@ public class ItemHelper(
     /// <returns>Tpl of cartridge</returns>
     protected string? GetRandomValidCaliber(TemplateItem magTemplate)
     {
-        var ammoTpls = magTemplate.Properties.Cartridges.First().Props.Filters.First().Filter;
-        var calibers = ammoTpls.Where(x => GetItem(x).Key).Select(x => GetItem(x).Value.Properties.Caliber).ToList();
+        var ammoTpls = magTemplate.Properties?.Cartridges?.First().Props?.Filters?.First().Filter;
+        var calibers = ammoTpls?.Where(x => GetItem(x).Key).Select(x => GetItem(x).Value?.Properties?.Caliber).ToList();
+
+        if (calibers is null)
+        {
+            throw new ItemHelperException("Calibers is null when trying to generate random valid caliber");
+        }
 
         return randomUtil.DrawRandomFromList(calibers).FirstOrDefault();
     }
@@ -1548,16 +1568,22 @@ public class ItemHelper(
         }
 
         var ammoArray = new ProbabilityObjectArray<MongoId, float?>(cloner);
-        foreach (var icd in ammos)
+        foreach (var ammoDetails in ammos)
         {
+            if (ammoDetails.Tpl is null)
+            {
+                logger.Error("Ammo details tpl is null when trying to draw ammo from pool");
+                continue;
+            }
+
             // Whitelist exists and tpl not inside it, skip
             // Fixes 9x18mm kedr issues
-            if (cartridgeWhitelist is not null && !cartridgeWhitelist.Contains(icd.Tpl.Value))
+            if (cartridgeWhitelist is not null && !cartridgeWhitelist.Contains(ammoDetails.Tpl.Value))
             {
                 continue;
             }
 
-            ammoArray.Add(new ProbabilityObject<MongoId, float?>(icd.Tpl.Value, (double)icd.RelativeProbability, null));
+            ammoArray.Add(new ProbabilityObject<MongoId, float?>(ammoDetails.Tpl.Value, (double)ammoDetails.RelativeProbability, null));
         }
 
         return ammoArray.Draw().FirstOrDefault();
@@ -1635,7 +1661,7 @@ public class ItemHelper(
     {
         var result = itemToAdd;
         HashSet<MongoId> incompatibleModTpls = [];
-        foreach (var slot in itemToAddTemplate.Properties.Slots)
+        foreach (var slot in itemToAddTemplate.Properties?.Slots ?? [])
         {
             // If only required mods is requested, skip non-essential
             if (requiredOnly && !(slot.Required ?? false))
@@ -1647,16 +1673,16 @@ public class ItemHelper(
             if (modSpawnChanceDict is not null && !(slot.Required ?? false))
             {
                 // only roll chance to not include mod if dict exists and has value for this mod type (e.g. front_plate)
-                if (modSpawnChanceDict.ContainsKey(slot.Name.ToLowerInvariant()))
+                if (modSpawnChanceDict.TryGetValue(slot.Name?.ToLowerInvariant() ?? string.Empty, out var value))
                 {
-                    if (!randomUtil.GetChance100(modSpawnChanceDict[slot.Name.ToLowerInvariant()]))
+                    if (!randomUtil.GetChance100(value))
                     {
                         continue;
                     }
                 }
             }
 
-            var itemPool = slot.Props.Filters.FirstOrDefault().Filter ?? [];
+            var itemPool = slot.Props?.Filters?.FirstOrDefault()?.Filter ?? [];
             if (itemPool.Count == 0)
             {
                 if (logger.IsLogEnabled(LogLevel.Debug))
@@ -1695,6 +1721,10 @@ public class ItemHelper(
             result.Add(modItemToAdd);
 
             var modItemDbDetails = GetItem(modItemToAdd.Template).Value;
+            if (modItemDbDetails?.Properties?.ConflictingItems is null)
+            {
+                continue;
+            }
 
             // Include conflicting items of newly added mod in pool to be used for next mod choice
             incompatibleModTpls.UnionWith(modItemDbDetails.Properties.ConflictingItems);
@@ -1842,8 +1872,13 @@ public class ItemHelper(
         var containerTemplate = GetItem(containerTpl).Value;
 
         // Get height/width
-        var height = containerTemplate.Properties.Grids.First().Props.CellsV;
-        var width = containerTemplate.Properties.Grids.First().Props.CellsH;
+        var height = containerTemplate?.Properties?.Grids?.First().Props?.CellsV;
+        var width = containerTemplate?.Properties?.Grids?.First().Props?.CellsH;
+
+        if (height is null || width is null)
+        {
+            throw new ItemHelperException("Height or width is null when trying to calculate container mapping");
+        }
 
         return GetBlankContainerMap(width.Value, height.Value);
     }