Having a personal relationship with your local gunshop helps. What you did was suspicious. I'd have worked out some sort of layaway deal up front and told them my plans and why. Use the $150 up front to layaway 3-4 guns and pick up one over the course of a few weeks. Gunshops are required to do some extra paperwork which can result in LE investigation if you purchase more than 1 handgun within a 7 day period. It looks an awful lot like you were working the system just to avoid that regulation. I've purchased 2 handguns at once in the past and the store where I did my business advised me that they would prefer that I pay for one today, and come back in a week or 10 days to pay for and pick up the 2nd one. I didn't have a problem with that. While it would have been legal to sell both I didn't see the need to raise red flags for either the store or me.