I just did a very unscientific experiment with a broken pair of cheap safety glasses. I shoot steel sometimes and always wear some type of shooting glasses. Sometimes at the public range I see people with none. I used an RWS 34 in .177 air gun to imitate shards of a bullet. The pellet is a pointed 7.8 grain. The gun is rated at 1000 fps. I figure this pellet is running at least 850-900 fps (sorry no chronograph). I know this is a pellet gun, however when shooting steel or anything else I know bounce back of the bullet or something else is always a possibility. On both shots the pellet was stopped with no pass through. One of the lenses got cracked. Anyway I figured the pellet was pass right through so I am impressed. Point of the story, ALWAYS WEAR SAFETY GLASSES AT THE RANGE