[lurkingknight]

you can also remove the first regular sized tooth on the rack to help with AoE, easiest thing to start with in terms of adjusting AoE, if it needs more adjustment, then you can shim between piston and piston head, or you can sorbo the cylinder head... sorbo is good because it will absorb some of the shock at the front of the gearbox.

Also, if your piston is full aluminum, it probably weighs more than a polycarb or poly fiber piston, trying to change direction of movement on something with much more inertia can lead to what you have there.