Perfect for the accuracy obsessed, expandable heads fly like field points. But you risk mechanical failure. And that's why the seemingly foolproof mechanism of the new PISTON POINT ($38 for three; 406-669-4141; pistonpoint.com) is creating such a buzz. This innovative head works like, well, a piston. On impact, the rear cylinder, which is connected to the tip by a shaft, thrusts forward with the full inertia of the speeding arrow to open the rear-deployment blades. These then lock into place and perform like fixed blades inside an animal. In flight, the head is .55 inch in diameter; after deployment it's 1½ inches. Ideal for deer and smaller game, the Piston Point is original and potentially groundbreaking.