i'll chime in again , only because I can speak to your original comment about working on the M1A /M14 family.
what is your experience? who has mentored or apprenticed you?
how many rifles have you built from the ground up? what "brands" ? just Chinese rinko plinkos? you are learning from youtube?? like funker tactical vids and tony ben shows? (no offense to them meant)
what tools and specific M14 gauges to you possess or have the drawings for to have made?
I've been building, diagnosing, repairing, customizing, living , breathing, eating and sh*tting the platform for nearly 10 years ( a hobby before that) , throw a box full of cream f the crop high end M14 parts on a table, I'll build you the best damn M14/M1A those parts could provide.... and hand make the custom composite stock to go on it...... but at the end of the day...... my piers still wouldn't sit by and let me call myself a "gunsmith" .
I wish you good luck

get past the CFO and municipal licencing , then the insurance...... then see how much loot you have left over for inventory and tools. it can be very gratifying, but then again, it can tear your fricken soul out too LOL