Slight optimization maybe?

lua/autorun/wowozela.lua

@@ -336,15 +336,17 @@ do -- sample meta
         if button then
             local wep = self.Player:GetActiveWeapon()
             local get = "GetNoteIndex" .. button
-            if wep:IsWeapon() and wep:GetClass() == "wowozela" and wep[get] then
+            if IsValid(wep) and wep:GetClass() == "wowozela" and wep[get] then
                 return wep[get](wep)
             end
         end
     end
 
     function META:CanPlay()
+        if not IsValid(self.Player) then return false end
+
         local wep = self.Player:GetActiveWeapon()
-        if wep:IsWeapon() and wep:GetClass() == "wowozela" then
+        if IsValid(wep) and wep:GetClass() == "wowozela" then
             return true
         end
 
@@ -590,16 +592,18 @@ do -- sample meta
         return -pitch / 89
     end
 
+    function META:StopPlaying()
+        if not self.WasPlaying then return end
+        for _, csp in pairs(self.Samples) do
+            if not csp.paused then
+                stop_sound(csp, self)
+            end
+        end
+        self.WasPlaying = nil
+    end
+
     function META:Think()
         if not self:CanPlay() or wowozela.disabled then
-            if self.WasPlaying then
-                for _, csp in pairs(self.Samples) do
-                    if not csp.paused then
-                        stop_sound(csp, self)
-                    end
-                end
-                self.WasPlaying = nil
-            end
             return
         end
 
@@ -735,15 +739,8 @@ do -- hooks
     end
 
     function wowozela.Think()
-        if not wowozela.KnownSamples[1] then
-            return
-        end
-
         for k, sampler in next, wowozela.Samplers do
-            if not IsValid(sampler.Player) then
-                sampler:Destroy()
-                wowozela.Samplers[k] = nil
-            else
+            if sampler:CanPlay() then
                 sampler:Think()
             end
         end
@@ -765,9 +762,18 @@ do -- hooks
                 wowozela.CreateSampler(ply)
             end
         end
+
+        for k, sampler in next, wowozela.Samplers do
+            if not IsValid(sampler.Player) then
+                sampler:Destroy()
+                wowozela.Samplers[k] = nil
+            elseif not sampler:CanPlay() then
+                sampler:StopPlaying()
+            end
+        end
     end
     hook.Add("Think", "wowozela_think", wowozela.Think)
-    timer.Create("WowozelaSlowThink", 0.1, 0, wowozela.SlowThink)
+    timer.Create("WowozelaSlowThink", 0.2, 0, wowozela.SlowThink)
 
     --[=[function wowozela.Draw()
         if not wowozela.KnownSamples[1] then

lua/weapons/wowozela.lua

@@ -242,6 +242,12 @@ if CLIENT then
         end
     end
 end
+function SWEP:_Think()
+    if self:GetOwner() and self:GetOwner():IsValid() and self:GetOwner():GetViewModel():IsValid() then
+        self:GetOwner():GetViewModel():SetNoDraw(true)
+        self.Think = nil
+    end
+end
 
 function SWEP:Deploy()
     self.Think = self._Think
@@ -253,16 +259,13 @@ function SWEP:Deploy()
 end
 
 function SWEP:Holster()
-    if CLIENT then
+    if not self:GetOwner():KeyDown(IN_RELOAD) then
         local ply = self:GetOwner()
-
-        if ply.wowozela_head_cb then
+        if CLIENT and ply.wowozela_head_cb then
             ply:RemoveCallback("BuildBonePositions", ply.wowozela_head_cb)
             ply.wowozela_head_cb = nil
         end
-    end
 
-    if not self:GetOwner():KeyDown(IN_RELOAD) then
         return true
     end
     return false
@@ -283,12 +286,7 @@ function SWEP:OnKeyEvent(key, press)
     end
 end
 
-function SWEP:_Think()
-    if self:GetOwner() and self:GetOwner():IsValid() and self:GetOwner():GetViewModel():IsValid() then
-        self:GetOwner():GetViewModel():SetNoDraw(true)
-        self.Think = nil
-    end
-end
+
 
 function SWEP:GetViewModelPosition(pos, ang)
     pos.x = 35575