god himself couldn't fix this shit

Content.Server/Weapons/Ranged/Systems/GunSystem.cs

@@ -224,7 +224,7 @@ public override void Shoot(EntityUid gunUid, GunComponent gun, List<(EntityUid?
                     {
                         var hitEntity = lastHit.Value;
                         if (hitscan.StaminaDamage > 0f)
-                            _stamina.TakeStaminaDamage(hitEntity, hitscan.StaminaDamage, source: user);
+                            _stamina.TakeStaminaDamageWithProjectileCoefficient(hitEntity, hitscan.StaminaDamage, source: user); // DeltaV - Cope with hitscan not being an entity
 
                         var dmg = hitscan.Damage;
 

Content.Shared/Damage/Systems/StaminaSystem.cs

@@ -1,14 +1,12 @@
 using System.Linq;
 using Content.Shared.Administration.Logs;
 using Content.Shared.Alert;
-using Content.Shared.Armor; // DeltaV
 using Content.Shared.CombatMode;
 using Content.Shared.Damage.Components;
 using Content.Shared.Damage.Events;
 using Content.Shared.Database;
 using Content.Shared.Effects;
 using Content.Shared.IdentityManagement;
-using Content.Shared.Inventory; // DeltaV
 using Content.Shared.Popups;
 using Content.Shared.Projectiles;
 using Content.Shared.Rejuvenate;
@@ -36,7 +34,6 @@ public sealed partial class StaminaSystem : EntitySystem
     [Dependency] private readonly SharedColorFlashEffectSystem _color = default!;
     [Dependency] private readonly SharedStunSystem _stunSystem = default!;
     [Dependency] private readonly SharedAudioSystem _audio = default!;
-    [Dependency] private readonly InventorySystem _inventory = default!; // DeltaV
 
     /// <summary>
     /// How much of a buffer is there between the stun duration and when stuns can be re-applied.
@@ -171,28 +168,8 @@ private void OnMeleeHit(EntityUid uid, StaminaDamageOnHitComponent component, Me
 
         foreach (var (ent, comp) in toHit)
         {
-            // Begin DeltaV code - melee stamina resistance from armor
-            var finalDamage = damage / toHit.Count;
-
-            if (_inventory.TryGetSlots(ent, out var slots))
-            {
-                var coefficient = 1.0f;
-
-                foreach (var slot in slots)
-                {
-                    if (!_inventory.TryGetSlotEntity(ent, slot.Name, out var equipped))
-                        continue;
-
-                    if (TryComp<ArmorComponent>(equipped, out var armor))
-                    {
-                        coefficient *= armor.StaminaMeleeDamageCoefficient;
-                    }
-                }
-
-                finalDamage *= coefficient;
-            }
-            TakeStaminaDamage(ent, finalDamage, comp, source: args.User, with: args.Weapon, sound: component.Sound);
-            // End DeltaV code
+            // DeltaV - Stamina damage coefficient
+            TakeStaminaDamageWithMeleeCoefficient(ent, damage, comp, source: args.User, with: args.Weapon, sound: component.Sound);
         }
     }
 
@@ -226,32 +203,8 @@ private void OnCollide(EntityUid uid, StaminaDamageOnCollideComponent component,
         if (ev.Cancelled)
             return;
 
-        // Begin DeltaV code
-        var damage = component.Damage;
-
-        // Check for armor on the target that might reduce stamina damage
-        if (_inventory.TryGetSlots(target, out var slots))
-        {
-            var coefficient = 1.0f;
-
-            // Check each equipped item for armor
-            foreach (var slot in slots)
-            {
-                if (!_inventory.TryGetSlotEntity(target, slot.Name, out var equipped))
-                    continue;
-
-                // If equipped item has armor component, multiply the coefficient
-                if (TryComp<ArmorComponent>(equipped, out var armor))
-                {
-                    coefficient *= armor.StaminaDamageCoefficient;
-                }
-            }
-
-            damage *= coefficient;
-        }
-
-        TakeStaminaDamage(target, damage, source: uid, sound: component.Sound);
-        // End DeltaV code
+        // DeltaV - Stamina damage coefficient
+        TakeStaminaDamageWithProjectileCoefficient(target, component.Damage, source: uid, sound: component.Sound);
     }
 
     private void SetStaminaAlert(EntityUid uid, StaminaComponent? component = null)

Content.Shared/DeltaV/Damage/StaminaSystem.Resist.cs

@@ -0,0 +1,87 @@
+using Content.Shared.Armor;
+using Content.Shared.Damage.Components;
+using Content.Shared.Inventory;
+using Robust.Shared.Audio;
+
+namespace Content.Shared.Damage.Systems;
+
+public sealed partial class StaminaSystem
+{
+    [Dependency] private readonly InventorySystem _inventory = default!;
+
+    /// <summary>
+    /// Gets the combined stamina protection coefficients from all armor worn by an entity
+    /// </summary>
+    private float GetMeleeCoefficient(EntityUid target)
+    {
+        var coefficient = 1.0f;
+
+        if (!_inventory.TryGetSlots(target, out var slots))
+            return coefficient;
+
+        foreach (var slot in slots)
+        {
+            if (!_inventory.TryGetSlotEntity(target, slot.Name, out var equipped))
+                continue;
+
+            if (TryComp<ArmorComponent>(equipped, out var armor))
+            {
+                coefficient *= armor.StaminaMeleeDamageCoefficient;
+            }
+        }
+
+        return coefficient;
+    }
+
+    /// <summary>
+    /// Gets the combined stamina protection coefficients from all armor worn by an entity
+    /// </summary>
+    private float GetProjectileCoefficient(EntityUid target)
+    {
+        var coefficient = 1.0f;
+
+        if (!_inventory.TryGetSlots(target, out var slots))
+            return coefficient;
+
+        foreach (var slot in slots)
+        {
+            if (!_inventory.TryGetSlotEntity(target, slot.Name, out var equipped))
+                continue;
+
+            if (TryComp<ArmorComponent>(equipped, out var armor))
+            {
+                coefficient *= armor.StaminaDamageCoefficient;
+            }
+        }
+
+        return coefficient;
+    }
+
+    /// <summary>
+    /// Applies stamina damage from melee attacks with armor resistance calculations
+    /// </summary>
+    public void TakeStaminaDamageWithMeleeCoefficient(EntityUid target, float damage, StaminaComponent? stamina = null, EntityUid? source = null, EntityUid? with = null, bool visual = true, SoundSpecifier? sound = null)
+    {
+        if (!Resolve(target, ref stamina))
+            return;
+
+        var coefficient = GetMeleeCoefficient(target);
+        var finalDamage = damage * coefficient;
+
+        TakeStaminaDamage(target, finalDamage, stamina, source, with, visual, sound);
+    }
+
+    /// <summary>
+    /// Applies stamina damage from projectiles with armor resistance calculations
+    /// </summary>
+    public void TakeStaminaDamageWithProjectileCoefficient(EntityUid target, float damage, StaminaComponent? stamina = null, EntityUid? source = null, EntityUid? with = null, bool visual = true, SoundSpecifier? sound = null)
+    {
+        if (!Resolve(target, ref stamina))
+            return;
+
+        var coefficient = GetProjectileCoefficient(target);
+        var finalDamage = damage * coefficient;
+
+        TakeStaminaDamage(target, finalDamage, stamina, source, with, visual, sound);
+    }
+}