Seems like it would be no different than if you bought it with a check or Credit card, in that case the BANK is providing the CASH based on your credit (same as your relative putting up the cash and your sending him/her a check to reimburse) you reimburse the bank with your payment, it's going through an FFL, YOU (the ACTUAL buyer) are doing the paper work, only possible glitch I see is if it's not a Ca. approved firearm.Otherwise it's perfectly legal.