You can not have a FFL only for buying.
You must sell so many guns in order to keep it.
I was going to get one many, many years ago when it wasn't that hard to do.
Had the forms all filled out, had a business license and a store front.
Even had the check written out to send in, then I re-read the whole thing over again just to make sure I had all that was needed when I saw at the bottom of the page that the BATF (no E on the end at that time) had the right to come in, unannounced and check you private collection.
Now I think my guns are all OK but I don't know for sure who may have had them or where some of them came from before I got them.
With all the paper work you have to keep for at least 10 years and their inspections, it ain't worth it unless you really intend to make it a full time business.
I have a friend who own a gun shop and for $20.00 or $25.00 he will run anything I buy from anyone through his books.
For that price, it ain't worth the hassle.
LONGTOM