Accuracy is not overly important with bear spray. Testing a can or two will make most people proficient. They have nifty inert canisters for just this purpose or lots of people just shoot off an expired can. Seems kind of foolish not to be familiar with any form of self defence you choose. Anyone that's taken a bear safety course has fired at least one canister. With the amount of companies now requiring this course I suspect the number is fairly high. I know most of my sheep hunting buddies have shot off a canister or two. Seems crazy not to if you are relying on it to possibly save your life. I know I've shot dozens.
I wonder how many people practice shooting at a target running rapidly at them. Likely a lot less than have shot off a canister of bear spray.
One other thing that should be noted is that the strength and volume of bear spray in much higher than that of personal defence sprays.
How much have you practiced with your rifle.