when i was 15, i was shooting at glass jars with a 22 and had a few small shards of glass fly back and hit me in the cheak and somehow a piece also got up under my safety glasses and landed in my eye. very scary experince luckily I didnt suffer any permanent damage to my eye, went to the ER they clamped my open and put 5 different types of drops in my eye then with some kind of tweasers the Dr. extracted the piece of glass from my eye. the piece that hit my cheak, left a nice scratch. but that was least of my worries I had to watch for infection in my eye for several weeks.

Since that experience i will never shoot at glass again and I highly advise against it. if you want to shoot something that breaks get ya a box of clay pigeons, walmart has a box of 90 for under 4 bucks. soemthing else thas fun is fill balloons with some corn starch or baking soda using a funnel adding about 2 table spoons, blow them up with air and tape them to a fence post when you shoot them it emits a white cloud of whatever you put in it. even pop cans full of water are pretty interesting even with a 22. have fun and be safe