Gun volume audit for .357 SIG + adjust SIG Sauer weights (#37670)

* Audit Sig Sauer P226

* Audit Glock 31 volume

* Audit Sig Sauer P320 in .357 SIG

data/json/items/gun/357sig.json

@@ -6,8 +6,8 @@
     "type": "GUN",
     "name": "SIG P226",
     "description": "A SIG Sauer P226 chambered for .357 SIG.  The P226 is a DA/SA, short-recoil operated semi-automatic pistol.",
-    "weight": "960 g",
-    "volume": "500 ml",
+    "weight": "964 g",
+    "volume": "549 ml",
     "price": 50000,
     "to_hit": -1,
     "bashing": 8,
@@ -27,6 +27,7 @@
     "name": { "str": "Glock 31" },
     "description": "A full size .357 SIG Glock pistol.  It is extremely similar to the Glock 22, and could be converted to fire .40 S&W by switching the barrel.",
     "weight": "660 g",
+    "volume": "443 ml",
     "ammo": [ "357sig" ],
     "magazines": [ [ "357sig", [ "glock40mag", "glock40bigmag" ] ] ]
   },
@@ -37,8 +38,8 @@
     "type": "GUN",
     "name": "SIG P320",
     "description": "The P320 is a semi automatic, short recoil operated pistol.  This one is chambered for .357 SIG.",
-    "weight": "751 g",
-    "volume": "500 ml",
+    "weight": "731 g",
+    "volume": "462 ml",
     "price": 69000,
     "to_hit": -2,
     "bashing": 8,