Ensuring functioning and poa/poi no doubt bit scary firing at a hard surface. If any one doubts what a round will do from personal experience when marking in the butts at the Swanbourne range in Perth as a young person one of the chaps was struck on the arm by a round that ricocheted 180 degrees it only bruised his arm thank goodness but was scary for a while. We thought somehow all the other rounds in the butts may have caused it do what it did it was highly irregular and in my 47 years of shooting since that event I have never heard of that happening again, well it wont now as we have electronics.