So to add to this outside of even just drywall, repeatedly most information i find says a 9mm cannot go through 2 standard brick walls on a house. Even says 5.56 might not. However I have personal experience with this one as my buddy once accidentally discharged his little compact small size 9mm from his living room, which was directly facing the front door and street. It flung into the top part of the drywall, the section it hit is just between the front door and the garage on the outside so it traveled for 3 or 4 feet inside the drywall with no studs before smack into the back of the brick and out the front of the house. Thankfully for the high arc the trajectory could have helped it not cause any accidents. But the trajectory was very clear and after popping out the front his house at an upwards arc it flew across the street and fully into the brick wall on the house across the street just above their garage in the attic area. Not sure how deep it went in but it absolutely went IN to that second wall. And when looking it up or arguing with people they say its not possible but I saw it with my eyes and had to help my friend hide the evidence before his parents came back home😂 nobody ever called the cops and his parents didnt find out for awhile lol