Score calculation and performance analysis of shooting targets is an important aspect in the development of sports shooting ability. An image-based automatic scoring algorithm would provide automation of this procedure and digital visualization of the result. Existing solutions are able to detect hits with high precision. However, these methods are either too expensive or adapted to unrealistic use cases where high quality paper targets are photographed in very favorable environments. Usually, precision pistol shooting is performed outdoors and bullet holes are covered with stickers between shooting rounds. The targets are reused until they are destroyed. This paper introduces the first generation of an image-based method for automatic hit detection adapted to realistic shooting conditions. It relies solely on available image processing techniques. The proposed algorithm detects hits with 40 percent detection rate in low-quality targets, reaching 88 percent detection rate in targets of higher quality.