The idea thai legering is a static form of fishing is not true. In a flowing river a swim can be explored just as effectively with a leger as it can with a float. The type of leger which will allow the bait to trundle along the river bed depends a great deal on the nature of the bottom. For example, a drilled bullet is ideal if the river bed is sandy. Choose a weight which just holds its position in the current but will begin to roll along as soon as you lilt the tip of your rod.
Cast across the river and allow your tackle to settle on the river bed. If no bites are fortheoming, raise the rod to set the leger trundling along until it comes to rest again. Hold the rod all the time and touch leger by holding the line between the finger and thumb. In this way it is possible to feel. Through the line, the actions of the leger rolling along the river bed. The leger will gradually work down and across the river until it reaches the nearside bank downstream from where you are fishing. The next cast can be made slightly downstream of the first, searching a fresh area.
On gravelly sections of river a swan shot link leger is better than a drilled bullet and will hold bottom easier with less weight. In a really fast (lowing, weedy river, a rolling leger can enable a bait to be presented in places where direct casts are impossible. Fish usually hide away under cover of the waving fronds of streamer weed, and the only way to present a bait to them is to allow the leger tackle to roll under with the force of the current.