In a come around your stone curls behind a guard and stays hidden: prerequisites, rotation, weight, reading the ice, common mistakes and safety.
The honest answer: a come around is a shot that curls around a stone and comes to rest behind it. The world federation's glossary says: "a shot that curls behind another stone" [1]. Club glossaries say the same, with the guard as the obstacle [2]. A guard is a stone placed so that it may protect another stone [1].
The come around is one of the shots where draw feel and ice feel come together. The US federation material advises: if the ice is fast and swingy, hits are hard, especially for beginners, so play draws and come arounds [3]. On slow, straight ice, on the other hand, you can't curl around guards and play tap-backs instead [3].
How hard is it? You need a secure draw and a guard to play around. There is no timeline.
Decide where the stone should end up: hidden behind the guard but still in the house. The come around is a draw shot, so the weight is that of a draw: the speed with which a stone just reaches the house [1].
Choose the rotation so the stone curls toward the target. The stone starts straight and only begins to curl after the break point [5]. For beginners, a handout gives 2–3 rotations for the length of the ice [6]. According to Curling Canada, advanced curlers use 4.5–5.0 rotations on strongly curling ice [5]. More rotation means: you need less ice, the broom stands tighter, sweeping is easier to manage, but stones finish harder [5].
Milestone: You can reproduce the rotations consistently (e.g., always the same two or three) and the stone turns cleanly.
The skip sets the broom outside the guard, not behind it. How far out depends on the ice. Draw the line to the broom (toe in the hack, hack knee and shoulders to the broom) [6].
The weight stays a draw: the national coaches describe that stone and body decelerate from the start of the slide and that you should learn where the stone sits on the deceleration curve [5]. Too much speed and the stone runs through the house, too little and it hangs up at the guard.
Milestone: Three of five stones come to rest behind the guard in the house or at the front edge of the house.
The team sweeps on skip command. In a come around, timing often decides: sweep early if the stone looks short, don't sweep when it fits exactly. Sweeping can make the stone travel further or curl more or less [7].
The US material warns: "Never bump on a come around freeze" [3]. The handout doesn't explain the sentence, so I pass it on only as a warning sign and don't interpret it. The material also says that you should rarely draw through a "port" (gap between two guards) [3].
More rotation can help you on swingy ice: Curling Canada advises advanced curlers on strongly curling ice to use 4.5–5.0 rotations, because the break point comes later and the team needs less ice [5]. Try it only when your release is consistent; otherwise you merely twist your cadence.
A come around is a shot that comes to rest behind another stone by curling around it [1]. The obstacle is usually a guard [2]. The stone is played as a draw, just with a greater curl distance.
According to US material, on fast, strongly swinging ice where hits are hard [3]. On slow, straight ice it doesn't work because the stone doesn't curl enough [3]. The skip and the ice decide.
A beginner handout gives 2–3 rotations for the length of the ice [6]. Curling Canada gives 4–5 for advanced curlers, up to 5.5 on strongly curling ice [5]. Another slide of the same document gives 4.5–5.0 [5]. Talk it through with your coach.
A line from the "Top Do's and Don'ts" list in US federation material [3]. The material doesn't explain it further. Ask your coach what it means in your situation; it is not part of the rulebook.
Hit and Stay in Curling: Hit and Stay Put Yourself