I composed this list when I first became interested in Doubles. I have added to it a couple of times. There is also an explanation of a few of the questions. Hope it helps. If I buy over the web I usually email it to the seller.

Shotgun Questions

1. Are there cracks or chips in the wood?
2. Is there evidence of repair to the wood?
3. Is the level of the wood lower than that of the metal? (proud metal)
4. Is the checkering sharp?
5. Has the checkering been finished over?
6. Does the guns metal appear refinished?
7. What is the length of pull to the front trigger?
8. Is the forearm loose?
9. What is the % of case color?
10. Is the engraving sharp?
11. What is the % of bluing?
12. Is the lettering on the blued surfaces sharp?
13. Are the screws damaged?
14. Is the lever right of center?
15. Is there movement between the barrel and receiver with the gun closed and the forearm removed?
16. Is there sideways movement between the barrel and receiver with the gun open?
17. Does the gun operate properly?
18. Are the trigger pulls light and crisp?
19. Do numbers match?
20. What is the length of the barrels?
21. What are the chokes?
22. Is there any pitting in the barrels?
23. Are there any dents or bulges?
24. Is there any metal pitting externally?
25. Has the gun been personalized with numbers, initials, etc.?

Concerning the question of how to check the bore; I look down the barrels and look for pits or darkening. A good 100 year old barrel will look just as smooth and shiny as a new gun. If you see ripples or waves they may have been honed and therefore thin. Look from the front as well as the rear, often imperfections do not show up looking from the rear only.

To measure the barrels for thickness requires the services of someone knowledgeable and you will probably have to pay for that. Also look for dents and run your hand down the barrels to feel for bulges. You can feel bulges that you sometimes cannot see.

Ringing the barrels is done by hanging them on your finger by the barrel hook and tapping them.. Most gun barrels will ring will ring when tapped by a pencil or something similar. The theory is that a dead sounding barrel may have a loose rib that deadens the ring. I have no experience with the proof of this theory but it does make sense.

Measuring the chokes is done by using a digital caliper to measure the bore at the muzzle and subtracting the nominal diameter of the bore. This will give you a number that may or may not reflect exactly how tight the gun patterns. It will get you in the ballpark

If the gun is really well refinished you will probably not be able to tell so, unless you are a serious collector, why should you care? If the gun is poorly refinished the sharp corners will be gone, the engraving will be thin in places, pits will show under the bluing, etc. To tell if case colors are original or not requires someone better than me. It has been my experience that if colors look good on a gun I own they look suspicious. If they look good on a seller’s gun they are exceptionally good. If the colors look good and the rest of the gun shows wear they are not original.

I, personally, will pay more for a gun that has been well refinished than I will for one that has no finish, but I am not a purist.