-The maximum case length after firing is 70mm (2.75").
-Maximum shot charge weight: 24.5g (0.86 ounce - about 7/8 oz.).
-In certain non-Olympic competitions, 1-1/8 oz. loads may be used if specified, but no national records can be set with them.
-Pellets: Must be spherical; must be lead, lead alloy, of similar approved material (plated or unplated); must not exceed 2.6mm (0.10") diameter.
-Rules state that "black powder, tracer, incendiary, or other specialty type cartridges are prohibited."
-You can't do anything special to the inside of the shell to increase the dispersion of the shot.
-Referees or jury members may unload from the gun and inspect any shooter's ammo.
-If they decide you used outlawed ammo, the jury may decide to score all your targets as "lost." If they decide you did it deliberately, you'll probably be disqualified.
-Ammo malfunctions must be decided by a referee.
-If the gun is at fault, a replacement gun may be used if it can be had within three minutes, or the round may be completed at a later time with the permission of the Chief of Referees.
-If you are the one who malfunctioned instead of the gun or ammo (say, if you used the wrong size shells), then you may be penalized for careless gun handling.

