Staples and air guns come in a plethora of sizes and configurations. One size does not fit all. Staples are sized and used according to the application. Some have broad crowns and short legs for fabric, and some have steel crowns and long legs that penetrate deep into framing studs.
Staples for pneumatic guns that are used for upholstery use lightweight, narrow crown staples. They typically have a 3/8-wide crown with 1/4-inch legs. If the staple is to be used in Naugahyde or soft leather, a wider crown can be used to keep the Naugahyde from pinching or dimpling. Most common upholstery air staplers can use both narrow and wide crown staples with legs ranging from 1/8 inch to 1/2 inch.
The bad boys are the big framing guns. These powerful air staplers can shoot a 3-inch steel staple through just about anything. They are used for joining studs together when home building, or anytime deep penetration is needed. Care must be taken when using this type of staple, as they can easily penetrate hands, shoes or flesh anywhere on your body. In addition, framing staples have a glue coating that makes them stay where they are fired.
When installing thinner paneling or sheets of any composite material, use a narrow gauge, brass staple. These are usually 3/4 inch in length with a 1/4-inch crown. Paneling staples also come with colored tops that allow you to select the right color to match the usage. Panel guns will also sink the head of the staple slightly. Panel staples are also very sharp and can easily penetrate fingers.
Trim and molding staples are also narrow crowned but are usually zinc. They come in sizes ranging from 1/2 inch to 1 inch in length and are used to secure thin pieces of molding or wood trim that needs extra holding power. They are also used to secure drawer components, cabinet drawer bottoms, cabinet backing or secure inset panels. Trim staplers also sink the head of the staple and are more powerful than panel guns.