Donna,
It depends on what the barrel length is and what catagory you will be shooting in. I am assuming this will be Bigbore competition (out to 200m)as apposed to field pistol/Hunters pistol (out to 100m). If you are going to use it in revolver class and want to shoot creedmore you should have at least a 7.5" barrel to get it out past your leg. You will also need a blast shield to protect your leg from barrel cylinder gap blast. Other position options if you have a shorter barrel are prone, off one or both knees etc but creedmore is by far the most stable. You could also shoot it in the Standing catagory. Field pistol/Hunters pistol is all shot standing and you can use reduced loads as it doesn't take near as much to knock down the 1/2 scale animals at the shorter ranges. Hope this helps. If you have anymore questions feel free to ask.
Bret