A fixed head will out penetrate a mechanical head, that’s a given. It’s the “failed to open” that I don’t buy. The first shot was most likely a shoulder or high backstrap hit that did not penetrate very far. I’d like to know exactly what head it was and see some pics. I’ve heard this failed to open excuse too many times only for it to be proven wrong. That seems to be the number one excuse for people that don’t like mechanicals and have very little experience using them.