Hi, my son has a Specna arms c-12 core. It's only a few weeks old and has been working fine, however yesterday it stopped firing bbs, the barrel is clear, and the mag is filled and setup correctly (have tried it on another gun). Battery is fine. It is making a firing sound (obviously slightly different tone as no bbs coming out). I've tried turning the hop down to relieve any pressure on the BBs. Any pointers on what to do/check next?