I don' t have any experience with brush buttons, but on the penetration question, there could be a number of factors. First, he is going to get more energy from his compound--they are more efficient, and he was shooting more weight. Is his draw length longer than yours? That will also make a considerable difference--55@30 will shoot harder than 55@26 due to the increased cast. Arrow flight could be another factor--arrows that are flying straight will out penetrate arrows that have a little wobble. Were his shafts smaller in diameter? Are they slicker? Two more contributing factors.

In my opinion, solid mediums are not a good example for testing how well an arrow will penetrate live game. A light, tiny shaft will outpenetrate a fat, heavy shaft on foam most of the time. Foam grabs, and the smaller shaft has less resistance. However, on a critter, you have fat and body fluids that lubricate, and you have skin and flesh that separate when cut. On a live animal, I think the only comparison would be whose arrow stuck further in the ground after a pass through.

Chad