There's a reason why many pawn shops have a large assortment of shotguns and other types of weaponry. Weapons are often one of the best things to pawn or sell; they have known value, they are usually fairly expensive, and you don't usually need them in your day-to-day life. But because a shotgun is a weapon (even if it's a collector's item), you need to do some special preparation.

Get Your Documentation Prepared

Like any collectible, a gun can have value beyond its manufacturing value. If your shotgun is an antique or is otherwise notable, you will want to be able to offer documentation to that effect. This is especially true if you've ever received an appraisal.

Clean Your Gun

Appearance almost always effects how much you'll get when you pawn or sell an item. A dusty stock may be hiding irregularities, scratches, or dents. Make sure to thoroughly clean your gun and bring it to the pawn shop in a carrying case, unloaded. Of course, always treat your gun as though it is loaded regardless.

The only caveat to this is: do not clean the gun if it is an antique. If it a true antique weapon, bring it down to the shop as is. 

Have Your License Ready

Many people don't realize they need a license to sell a gun as well as to purchase a gun. After all, the pawnshop will need to know that you had the gun legally and that you will be able to get it back from them later on. Make sure you have a copy of your gun license when you go to the shop.

Look Your Gun Up on the Internet

Before going down to the shop, look up third party marketplaces to find the resale value of your gun. Most people don't remember exactly how much they purchased their guns for, especially if it was purchased second hand or at an event. Knowing what the going rate is for your weapon will help in negotiations.

Don't forget that you also need to prepare yourself for getting your weapon back. In certain areas, you may need to re-submit to a background check and certification processes in order to get your weapon back once you've pawned it. Make sure that you'll be able to get the clearance that you need; otherwise you may not be able to get your shotgun returned to you even if you're able to pay for it.