So you’ve decided to take up tournament archery. Welcome to the party.Although it’s been around for centuries, competitive archery is in the midst of a huge growth period. We’re seeing more tournaments, more competitors at those tournaments and bigger payouts for top finishers.Some of the tournaments are outdoors. Others are indoors. As you assemble your tournament gear, it’s important to have a set of arrows for shooting indoors, and a set for outdoor competitions.What’s the difference?Generally speaking, many archers will shoot larger diameter arrows indoors and smaller diameter arrows outdoors. The “fat” arrows are built for cutting scoring lines, while the “skinny” ones are meant to cut through wind. That’s a simplistic generalization, and there are many exceptions. But here are the guiding factors.At indoor tournaments you don’t have to worry about wind or rain, and shot distances are usually 18 meters or 20 yards.Outdoors, you have to contend with whatever Mother Nature throws at you, and you might be shooting at targets up to 90 meters away.When shooting indoors, many compound archers shoot arrows that are as large as legally allowed. (World Archery allows arrows up to 9.3mm (23/64”) diameter, while many other organizations allow up to 10.7mm (27/64”).)Those fat arrows are commonly called “line-cutters,” because they cover more area of the target than skinny arrows. You can cut a scoring ring with a fat arrow that you’d miss with a skinny one. And as long as your arrow is touching a scoring ring, you get the higher point value.Archers who use fat arrows tend to fletch them with 4- or 5-inch feathers for maximum spin and stability. Long, tapered points as heavy as 150-300 grains further aid arrow guidance. Consistent arrow flight is what’s most important to archers at indoor events.Olympic recurve archers don’t necessarily follow the fat-arrow trend indoors. If they’ve got an outdoor arrow that’s performing well, they might stick with it just to maintain consistency.Some do switch to larger diameter arrows when they head indoors, however. They just won’t be quite as large as the ones the compound archers use, because those very stiff arrows don’t fly well out of an Olympic recurve. A 2312, aluminum shaft is popular for indoor recurve archers. Its diameter is 9.1mm.Shooting outdoors at spot faces, many compound archers are going to shoot small diameter arrows fletched with shorter, low-profile or shield cut vanes. Here, the emphasis is on aerodynamics to slice through wind and rain at long distances.An exception is 3-D archery. You’ll still find compound archers shooting fat arrows to cut scoring rings on 3-D targets, but they generally will have short, low-profile vanes and lighter points to keep the arrows light and fast. Also, 3-D archers typically don’t shoot over 50 yards.Olympic recurve archers shoot small diameter arrows outdoors. They’re usually fletched with lightweight, curled-style vanes designed to promote maximum spin, which is key to arrow flight in the wind.