Hi,
On the CPSA website in
Booklet No 5 it says the following on page 2-1.
The maximum loads for each discipline are: Domestic Sporting and Trap 28grams (1oz), Olympic Skeet,
Olympic Trap and Double Trap, 24grams, FITASC Sporting 28grams and Helice 36grams. All
competition rules forbid the use of “Black Powder”, “Tracer” and “Reloaded” cartridges. The size of shot
in the cartridge is indicated by a number; for clay target shooting the most commonly used sizes are UK 6,
7, 7½, 8, 9 and 12; six being the largest and twelve the smallest.