Grenadier, thanks for the reply. That's useful info to know. I was expecting to pay a deposit, just not that large. Since the project was estimated to take several years, I didn't think that paying in installments would be a problem. And demanding $100 to ship back my action--when it only cost me $45 USPS insured to ship to him--seemed quite rude. He hadn't done any work on it. Maybe it's a "consulting fee"? The whole experience has kind-of soured me on getting a custom rifle built.
If I have to send him a payment to get my action back, should I use a postal money order? I want to avoid any funny business.