M14 won't auto fire.
 

It's a echo 1 m14 RIS. It will semi fire but won't go full auto.

http://www.airsoftcanada.com/showthread.php?t=120774

When I got the gun the guy sent two 8.4's with it. Could using a 8.4 not a 9.6 cause damage to the gun?

I believe whoever had your gun last or used it last either broke or disconnected this
http://echo1usa.com/English/bmz_cach...ge.380x285.jpg

Cause the M14 fires semi naturally

Thanks I open the gun up and found the part you showed me to be broken and super glued to the mech box, yupe the last owner of this gun was a real winner.