The trap house for American singles is located 16 yards in front of the five shooting posts arranged in an arc. The house itself sits about 2 ½ feet above ground and has one machine that oscillates horizontally. The athlete that starts on post one (far left of the field), is designated the squad leader. 

The squad leader always calls for their target first regardless of what post they are on. Once the squad leader has shot their first target, the athlete on Post 2 will call for their target. The progression will continue until the Post 5 athlete shoots their target; after which, the squad leader will shoot their next target. After all athletes have shot five shells, the athletes will rotate posts to their right. (i.e., The athlete on Post 5 will rotate to Post 1 by walking behind the other athletes.) This will continue until all athletes have shot 25 shells. 

During the round, the machine randomly oscillates horizontally and throws targets at angles up to 17 degrees right or left of center. It is important to note that legal targets can be up to 27 degrees right or left of center. The targets are released manually or by using a voice-activated mechanism when the athlete calls for the target. 

A match usually consists of 100 targets, and participants are allowed one shell for singles. The Amateur Trapshooting Association (ATA) regulates American trap singles. 

Link to the ATA rule book.