bolt stuck

Hello, I have a UTG L96 that was working fine not too long ago, and now its taking wayyy too much force to rack the bolt forward and seat it. Its sounds like something is grinding somewhere. Without the spring guide arm, the bolt easily slides back and forth in the receiver. No problem, no...

When my tsd sd700 vsr10 imitation (same gun as well mb03) is cocked, the bolt will not slide all the way forward. Instead, it will still have a couple milimeter to go, causing the cylinder head to not go far enough into the hopup bucking. The gun still shoots, but there is a major compression...