Staff Sling: A staff sling is simply a pole of four or more feet in length
with a pocketed thong of some sort fixed to its top end.

The missile to
be slung is placed in the widest portion of the thong, the free end
grasped, and the staff swung forcefully, either sideways on an ascending
curve or from the rear to overhead. At the proper time the
free end of the thong is released, and the momentum of the swing carries
the missile to its TARGET. Note that the staff sling is much the same
as a miniature siege machine. Its principal USE is the hurling of small,
relatively heavy missiles over some intervening obstacle, such as a
wall. It is slower to USE and less accurate than a normal sling, but it
throws heavier missiles on a high trajectory. It does not have the
range of a normal sling. It is so difficult to hit targets near to the slinger
that for all practical purposes, the staff sling always operates at medium or
long range only. If combustibles or like materials are
slung with it, the Grenade-like Missile Table in the DMG should be used to determine results.
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Staff Sling
Weapon Type Approximate
Weight in
Pounds
Size S or M Size L   Notes  Length Space 
Required
Speed 
Factor
0 1 2 3 4 5 6 7 8 9 10
Staff Sling 5 1-6 1-6 - 5' 6' 11 0 0 0 0 0 0 0 0 0 0 0

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Staff Sling Bullet
Weapon Type Approximate
Weight in
Pounds
Size S or M Size L ROF S M L 0 1 2 3 4 5 6 7 8 9 10
Staff Sling 0.5 2-8 3-9 1/2 - 3-6 9 -5 -4 -3 -2 -1 0 0 0 0 0 0

Staff Sling Stone
Weapon Type Approximate
Weight in
Pounds
Size S or M Size L ROF S M L 0 1 2 3 4 5 6 7 8 9 10
Staff Sling 0.4 1-8 2-8 1/2 - 3-6 9 -6 -5 -4 -3 -2 -1 0 0 0 0 0