I hope this is not too overpowered. I tried to make the battery on the armor weak and also made his weakness something as trivial as snow. Hope you like! Link about the helmet: http://www.minemaarten.com/wikis/pneumaticcraft-wiki/pneumaticcraft-wiki-charging-station-pneumatic-items/pneumaticcraft-wiki-pneumatic-helmet/
More in-depth parts on the weapon: X17 Railgun Burst Rifle: Custom-made 3-round burst gun that uses electromagnets to pull the bullet out of the barrel at mach 5. The bullets are steel, but can not be customized at all. The power armor holds 5,000,000 kilojoules of electricity, but only lasts 5 hours. Very expensive to recharge. Backstory He spent most of his kithood procrastinating on schoolwork and fiddling with circuits. As he got older, he acquired *coughcoughstolecoughcough* some powerful metal and worked it with some wiring and such, making his power armor. He ran out of the metal, so he had to use steel for his gun and helmet. He also overlooked the fact that he kept the air conditioning on in the armor even when in cold areas, so that he would be supercooled while in cold places. Snowballs are his main weakness. When a heedless rebel came to his house and explained everything, Ender thought, "Awesome! I need to join!" He grabbed his stuff and ran.
