When someone is suicidal and set, they often act in the moment. In these cases, gun shots are fatal. Even veterans are now facing higher suicide rates, and of the veterans who do commit suicide, almost 70% look to guns due to easy access.
You need thirty bullets in under a minute to kill something? What are you hunting? A wooly mammoth? A T-Rex? I think everything that requires that much ammunition to kill was wiped out by human beings or nature a long, long time ago.