I am familiar with the machinist's level and own one (use it for checking heads and engine block decks).
I have been considering a gunsmith but I enjoy doing this kind of stuff. I'm the same way about my cars... I don't let anyone else touch them... The thought of another man/woman with their hands all over my Z28's engine makes me shake.
James K: That one didn't make the coffee go... but it did make the head shake.
When I die better bury me deep, two .45s layin' at my feet,
An M16 across my chest, tell Chesty Puller I did my best