Do a google search on your M14 Federal Ordnance they do not get much respect.
It is a semi auto gun, and you are posting in the section discussing full auto guns.
Anyway it's like any other crap shoot where some company makes receivers and tears apart old machineguns for spare parts, if the machinegun your parts came from was new, then your gun is like new, if it saw 20yrs of hard jungle fighting then got a new paint job, it is a worn out gun with a new paint job.
I had a Chinese Polytech M14 with the same reputation it functioned fine but any round fired in that gun, the brass even when loaded on a small based sizing die would never chamber in any other gun.
Hopefully your gun has seen enough use that it is past the stage that a problem part is going to cause it to blow up.
I saw one new that one the third round fired the case was blown out to a straight wall as the barrel separated from the receiver. Federal Ord exchanged the gun of course and no one lost an eye.