I am not a Physicist or a professional firearm designer, but something tells me Smith & Wesson has at least one of them on staff. I am also betting that when they designed the SD9 they did so with intention of it working and being at least minimally durable. I will further bet that they tested the design and were pleased with it. And gosh golly they were successful because my SD9's are accurate, reliable and so far very durable. So my score card reads: Reality 1 - Physics 0.