Hoping to get some input on transferring an AR-15 rifle to my wife's Grandpa. Heres the situation. A few days ago (just after Obama went on TV talking about gun control) I was over at my wife's grandparents house and we were discussing the issues around assault rifles and the second amendment in general. I had just recently purchased a MP-1522 and had plans to get a .223 AR before things went crazy with stock/prices. I was telling him how I had hoped to be able to afford an AR15 before any possible ban would go through. He is a gun owner and NRA member as well and fully supports the right to bear arms. He was asking me how much one would cost and I explained the prices were jumping up and availability was dwindling.
To my surprise, he gave me a check and said "Go out and get yourself one." I told him i would pay him back. I went and cashed the check and with money in hand started calling all around. We have five local gun stores and I knew it was probably going to be impossible to find one. But, my last phone call, the gun store told me they had two on consignment. I asked them to hold them back till I got off work to look at them. When I got there, one was a MP15 and the other a Bushmaster. This local store had elevated prices but were not gouging. Knowing I had enough to buy both, I purchased both rifles and completed the FFL background check and left with the two rifles and some ammo.
Fast forward a week. After checking out both rifles I decided I only wanted to keep one.(and the wife only wanted me to keep one) The MP15. I asked if her grandfather would be interested in the other. He said sure. Here is where my question is.
However, I want the transfer to be 100% legal. Do I;
A. Just transfer the rifle to him with a simple bill of sale/gift receipt.
B. Take him to the local gun store and do a FFL transfer.
Although he fully gifted the money to me to by the rifles, me simply transferring the gun to him might be looked upon as a "straw sale"? I just want to make sure we go about it the right way. Both rifles are still in my possession and will remain as such until I find the best way to go about this.