I've had many e-mails over the years asking how to tell if a used SIG is still in good shape or not. After writing the same e-mail over and over for the last five years, I figured it was time to post my thoughts on what to look at when you're going to inspect a SIG Sauer pistol for wear.
The first thing to look at is the frame rails. The rails will tell you everything that you need to know about how well the gun has been taken care of.
The following is how the color of the Anodizing of the SIG frame will change as your gun wears.
1 Dull Black - No wear, perfect finish.
2 Shiny Black - Slight wearing in of the pigment in the anodizing, this is normal after about 200 to 500 rounds.
3 Dark Gold/Orange - The pigment in the anodizing is starting to wear, this is perfectly normal and not a problem, the metal is still protected and your frame is still perfectly viable. Most guns reach this phase between 2,000 and 4,000rounds.
4 Bright Gold - The pigment in the anodizing is wearing in. Your frame is still protected and your gun is still perfectly useable. Most guns reach this phase and remain static from here on out as long as proper lubrication is used.
5 Light Gold - The pigment in your anodizing is wearing through, your frame is still protected, but you should keep an eye on it.
6 Shiny Silver - This is where you need to start being cautions. The pigment in the anodizing is worn through, your frame is still protected, but you need to monitor your frame rails very closely and make sure they remain greased thoroughly for the rest of your gun's life.
7 Dull Silver - No Anodizing. Your anodizing has worn completely through in the areas you see dull silver. From here on your frame is unprotected and it's time to consider a new gun. It may still shoot and function perfectly, but your frame rails will continue to wear at an accelerated rate.
The next thing to look at is the disconnector tab on your trigger bar. That's the part of the trigger bar that sits up highest in the frame. A factory new trigger bar will have a nice radius across the top, a heavily used one will have a flat worn into it. The best way to check and make sure it's still functioning correctly is to pull the slide back by about 1/4"� or so and pull the trigger, if the trigger is slack you're OK. If you feel a click and resistance before the trigger reaches the frame, your disconnector is in need of replacement.
The next place to look at is the barrel. You will notice the "smileys"� on the barrel at the muzzle end. If you run your finger down the barrel and feel a dip, you may want to have the gun looked at by a professional, the slide should not be abrading the barrel enoughto remove any material at all. The presence of a dip in the metal could indicate that your slide has a burr in it, which should be attended to immediately.
If you look at the front of the chamber section at the top of the barrel you will see a ledge that steps down just before the tube part of the barrel starts. The ledge there should be at a clear 90 degree angle, any rolling of that sharp corner would indicate a soft barrel or one which hasn't been lubricated properly.
The slide should also be inspected.The slide lock lever detent on the slide should be looked at for burrs or any rounding on the rear or the notch. A burr sticking out can abrade your thumbs if you shoot a thumbs forward grip.
You can see the fade of the rails in these 2 pics. This gun has been on my hip for years and is still my Primary EDC.