FFL Side Hustle

Maybe Prop can chime in but I don't think it is worth it as a side hustle because of the headaches you deal with. Low margins and dealing with all of that paperwork seems like a pain in the arse.

Not worth it as a side hustle. If you just want an FFL go ahead and get one it's only $175 for 3 years. You won't be able to be competitve with online pricing or presence with a "side hustle" budget. The major online retailers are able to leverage buying power with volume and cost average on large lots well below what your cost on guns from major manufacturers will be from distributors. There is no margin in retailing guns from major manufacturers. B&M stores make their money selling accessories, services and other items. You also won't be able to get the really popular or new guns with any regularity since you won't be spending enough with your rep to warrant them giving you their allocations.

As far as the transfers go, if you are doing this part-time I am assuming you have a regular day job. Transfers are delivered during regular work hours via UPS, FedEx and USPS. If you don't have someone who is going to be home to accept your packages then you are going to spend a lot of time after work picking them up. There is also a security risk advertising that you have a lot of guns at your house and people knowing when you will and will not be available (aka knowing when you will and will not be home). You may choose to spend extra money on a security system or insurance to cover a potential loss which adds to the overhead of your side hustle. I don't know how much business you would be able to steal away from local B&M FFLs doing transfers who have regular hours. If you are going to be relying on transfers to make side cash, what can you bring to the table to grab customers away from their regular FFL considering you are going to be harder for them to deal with because of your limited availability?

If you are going to be doing this from your house you will need to know that zoning will approve your business. Some localities are more strict that others.

Not even close to worth it

I would not mess with it.
A lot of headaches and not a lot of money.
A friend asked me to bail him out of his gun shop.
I looked at the numbers and you would be trading cash over the counter no real profit.