diff --git a/Mirror/Weaver/Extensions.cs b/Mirror/Weaver/Extensions.cs
new file mode 100644
index 000000000..d14fb5987
--- /dev/null
+++ b/Mirror/Weaver/Extensions.cs
@@ -0,0 +1,19 @@
+namespace Mirror.Weaver
+{
+    public static class Extensions
+    {
+        // string.GetHashCode is not guaranteed to be the same on all machines, but
+        // we need one that is the same on all machines. simple and stupid:
+        // IMPORTANT: needs to be same one as in HLAPI
+        public static int GetStableHashCode(this string text)
+        {
+            unchecked
+            {
+                int hash = 23;
+                foreach (char c in text)
+                    hash = hash * 31 + c;
+                return hash;
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/Mirror/Weaver/Mirror.Weaver.csproj b/Mirror/Weaver/Mirror.Weaver.csproj
index 3a2875ff6..6aa67d1a0 100644
--- a/Mirror/Weaver/Mirror.Weaver.csproj
+++ b/Mirror/Weaver/Mirror.Weaver.csproj
@@ -66,6 +66,7 @@
   </ItemGroup>
   <ItemGroup>
     <Compile Include="AssemblyInfo.cs" />
+    <Compile Include="Extensions.cs" />
     <Compile Include="MessageClassProcessor.cs" />
     <Compile Include="MonoBehaviourProcessor.cs" />
     <Compile Include="Program.cs" />
diff --git a/Mirror/Weaver/UNetBehaviourProcessor.cs b/Mirror/Weaver/UNetBehaviourProcessor.cs
index d3071fab1..5d38a8fae 100644
--- a/Mirror/Weaver/UNetBehaviourProcessor.cs
+++ b/Mirror/Weaver/UNetBehaviourProcessor.cs
@@ -240,7 +240,7 @@ void GenerateConstants()
             {
                 FieldReference cmdConstant = Weaver.ResolveField(m_td, "kCmd" + md.Name);
 
-                int cmdHash = GetHashCode(m_td.Name + ":Cmd:" + md.Name);
+                int cmdHash = (m_td.Name + ":Cmd:" + md.Name).GetStableHashCode();
                 cctorWorker.Append(cctorWorker.Create(OpCodes.Ldc_I4, cmdHash));
                 cctorWorker.Append(cctorWorker.Create(OpCodes.Stsfld, cmdConstant));
                 //Weaver.DLog(m_td, "    Constant " + m_td.Name + ":Cmd:" + md.Name);
@@ -254,7 +254,7 @@ void GenerateConstants()
             {
                 FieldReference rpcConstant = Weaver.ResolveField(m_td, "kRpc" + md.Name);
 
-                int rpcHash = GetHashCode(m_td.Name + ":Rpc:" + md.Name);
+                int rpcHash = (m_td.Name + ":Rpc:" + md.Name).GetStableHashCode();
                 cctorWorker.Append(cctorWorker.Create(OpCodes.Ldc_I4, rpcHash));
                 cctorWorker.Append(cctorWorker.Create(OpCodes.Stsfld, rpcConstant));
                 //Weaver.DLog(m_td, "    Constant " + m_td.Name + ":Rpc:" + md.Name);
@@ -268,7 +268,7 @@ void GenerateConstants()
             {
                 FieldReference targetRpcConstant = Weaver.ResolveField(m_td, "kTargetRpc" + md.Name);
 
-                int targetRpcHash = GetHashCode(m_td.Name + ":TargetRpc:" + md.Name);
+                int targetRpcHash = (m_td.Name + ":TargetRpc:" + md.Name).GetStableHashCode();
                 cctorWorker.Append(cctorWorker.Create(OpCodes.Ldc_I4, targetRpcHash));
                 cctorWorker.Append(cctorWorker.Create(OpCodes.Stsfld, targetRpcConstant));
                 //Weaver.DLog(m_td, "    Constant " + m_td.Name + ":Rpc:" + md.Name);
@@ -282,7 +282,7 @@ void GenerateConstants()
             {
                 FieldReference eventConstant = Weaver.ResolveField(m_td, "kEvent" + ed.Name);
 
-                int eventHash = GetHashCode(m_td.Name + ":Event:" + ed.Name);
+                int eventHash = (m_td.Name + ":Event:" + ed.Name).GetStableHashCode();
                 cctorWorker.Append(cctorWorker.Create(OpCodes.Ldc_I4, eventHash));
                 cctorWorker.Append(cctorWorker.Create(OpCodes.Stsfld, eventConstant));
                 //Weaver.DLog(m_td, "    Constant " + m_td.Name + ":Event:" + ed.Name);
@@ -1908,30 +1908,6 @@ void ProcessSyncVars()
             Weaver.SetNumSyncVars(m_td.FullName, numSyncVars);
         }
 
-        // Copy of Mono string.GetHashCode(), so that we generate same hashes regardless of runtime (mono/MS .NET)
-        private static int GetHashCode(string s)
-        {
-            unsafe
-            {
-                int length = s.Length;
-                fixed(char* c = s)
-                {
-                    char* cc = c;
-                    char* end = cc + length - 1;
-                    int h = 0;
-                    for (; cc < end; cc += 2)
-                    {
-                        h = (h << 5) - h + *cc;
-                        h = (h << 5) - h + cc[1];
-                    }
-                    ++end;
-                    if (cc < end)
-                        h = (h << 5) - h + *cc;
-                    return h;
-                }
-            }
-        }
-
         bool HasMethod(string name)
         {
             foreach (var method in m_td.Methods)