Should the firing pin in my Ruger 10/22 be hitting the edge of the shell casing?

I went shooting this week and noticed that the firing pin is hitting the edge of the shell casing i am using Remington .22 LR Rimfire Ammunition and i take it the whole butt of the shell is the primer. At the very edge of the casing is being nicked to set off the round is this normal? I just bout this about 2 weeks ago and have only shot it 2 times and i have noticed it both times. When i looked at my dads 40 cal SW it had a primer in the middle. My Grandpas 30/30 also had a primer on the butt. I don't know if this is normal or not for a Ruger 10/22 to do that or not.