6a. Legal Pinfall
Pins to be credited to a player following a legal delivery shall include:
1. Pins knocked down or off the lane surface by the ball or another pin.
2. Pins knocked down or off the lane surface by a pin rebounding from a side partition or rear cushion.
3. Pins knocked down or off the lane surface by a pin rebounding from the sweep bar when it is at rest
on the pin deck before sweeping dead wood from the pin deck.
4. Pins that lean and touch the kickback or side partition. All such pins are termed dead wood and
must be removed before the next delivery.
No pins may be conceded, and only pins actually knocked down or moved entirely off the playing area
of the lane surface as a result of a legal delivery may be counted.
6b. Illegal Pinfall
When any of the following occur, the delivery counts but the resulting pinfall does not:
1. A ball leaves the lane before reaching the pins.
2. A ball rebounds from the rear cushion.
3. A pin rebounds after coming in contact with the body, arms or legs of a human pinsetter.
4. A pin is touched by mechanical pinsetting equipment.
5. Any pin knocked down when dead wood is being removed.
6. Any pin knocked down by a human pinsetter.
7. The player commits a foul.
8. A delivery is made with dead wood on the lane or in the gutter and the ball contacts such dead
wood before leaving the lane surface
http://usbcongress.http.internapcdn.net/usbcongress/bowl/rulebook/2012-2013Rulebook/Rulebook_12-13.pdf