the furthest targets on a perfectly still day with a little practice, mastering shooting in wind can take many years. Pellets can be blown sideways by even a light breeze. At longer distances this can start to cause misses, as the pellet will often be blown onto the faceplate if aimed centrally. In stronger winds it is not uncommon to have to aim completely off the faceplate in order to score a hit, and judging the amount of compensation to apply takes a lot of practice and experience. Head and tail winds can also have an effect on the trajectory of the pellets, causing them to hit high or low. It is common to fit a “windicator” to the barrel of the rifle – a piece of light cord with a feather on the end will provide a good indicator of general direction in light winds when it may not be entirely obvious, but it does not indicate what the wind will be doing on the way to the target. Competitors may choose to lift the reset cord of a target off the ground to get a feel for this wind – it will arc gently in a steady crosswind, and may even reveal changes in wind direction caused by nearby trees and foliage. Although many scopes have mechanical adjustment for horizontal offset, it is primarily used to ensure the rifle is shooting straight ahead in still conditions. The variable nature of the wind means it is often easier to aim off target (sometimes called "Kentucky windage" in the US) than to try to adjust the calibration of the crosshairs. One measure of the difficulty of a field target shot is the Troyer (named after Brad Troyer). At its simplest, a Troyer is the distance to the target in yards divided by the kill zone diameter in inches. (This can be adjusted to meters/millimeters by multiplying by 2.32.) Thus, if a target is at 45 yds and the kill zone is 2 in, the difficulty is 45/2 or 22.5T. In practice, there are additional multipliers for various conditions such as targets over 45 yards, wind, "extremely" dark or bright conditions, standing or kneeling positions, and uphill or downhill shots. A typical course has a difficulty averaging about 25T with a spread of difficulties from as low as 10T to as high as 60T. A well-designed course can be used for