I find the most challenging part to be working with strictly yes/no questions, but it's that restriction that makes it fun.
A comment:
The man was not at home, yet knew where to get a gun intimately enough to not even consider another alternative, which suggests he either carries a gun, or operates for a lengthy amount of time somewhere where he could easily do so.
Is the man any of the following: policeman, soldier, gun store salesman, hunter?