If I had to guess, the bass are probably clamping your bait. I really believe that a lot of times when a bass hits a Big Hammer, it thinks that its hitting a bluegill and it grabs the bait by the head and tries to crush it. Bass I think know that bluegill are spiny fish, so they try to kill them, then turn them around and eat them. When you get drilled on the Big Hammer and swing and the bass shoots straight up and spits it, I think a lot of times you don't even have the hook in the fish because the fish was just clamping down on the leadhead. Sometimes all you can do is set as hard as you can and then keep setting the hook. Going up to 20 or even 25lb test can help too. There's too much stretch in 10-15lb a lot of times.