Ok, my friend has a fire hawk, he striped the piston so sent it away to a 'tech' to fix, he sent it off with some new duel sector gears, new piston and a m110 spring!
It's come back and is only firing at 95-100 fps, does anyone have any idea why this is? I've checked the piston/cylinder head/ nozzle for compression which seems fine! He and I are at out wits end with this gun! Please help!!