For Electricity & Magnetism in the Fall 2012 semester, I worked in a team of four to build a coil gun and test the effect of projectile material and geometry on launch performance. I built a small coil gun and we shot projectiles constructed from iron, various steel alloys, aluminum and mu-metal in solid and hollow configurations of various lengths. Furthermore, we predicted the performance of the gun with reasonable accuracy using various mathematical models and finite element simulations. We found that iron projectiles with large cross sectional area produced the highest exit velocities. Steel and hollow projectiles produced lower velocities and length was found to not matter substantially.