I just noticed now that Z uses the term "triger mech".

Is this an abbreviation (as used by Z)? There’s no punctuation to indicate it. Is it a common term/short form? Do people say "the gun had a faulty trigger mech, so I bought a new one"?

In short, could it be significant to an extent? Indicating a particular occupation, perhaps – or a particular interest in guns, beyond what you’d call normal? The latter has been discussed many times – was Z a hunter, gun buff, someone who frequented shooting ranges, etc? Could his use of this term (if it IS a term and not just a written abbreviation – albeit without punctuation, as said already) be viewed in this light?

Just speculating.