if they took the safe, then they knew it was there to begin with and brought the right kind of vehicle so they can can haul it out. like a truck
although we like to just chalk up firearms theft as a happenstance, it rarely is. someone knew or heard of him having a lot of guns, he may even inadvertently told someone, maybe the thief himself, we all like to brag about our collections to anyone that will listen if the subject of guns comes up.
or it could well been a family member, close or not so close that's on drugs and sees a golden opportunity to get his druggie pals to help in the theft, especially if they know the family schedule, work, vacation. all families have a druggie or a low life scum somewhere in their family tree, if you have a large extended family, well that just mean there will be more then one of those low life scums.
my bet it was a "inside" job, rather then someone just breaking it and it was just blind luck they broke into a gun guy's house.
then there is the whole "social media" craze, ie FACEBOOK, where not only do people put in their vacation time etc.... but also post about the guns they have. stupid, stupid, stupid.
I will leave you with this; for every one person you tell that you have guns ie. family, friends etc..... that number exponentially increases as they tell someone else, who tells someone else etc.... and if you put that on a "social media" site. well, you just told everybody with a computer what you have, what your schedule is and your address.