Graybeard
There are about 60 million gun owners in America. They own about 300,000,000 firearms, or about 5 firearms per gun owner. I think your assumption that there are 10 or 15 firearms per gun owner is off the mark. It is still a big number. I am not convinced about these statistics because they indicate that over 90% of all gun owners are men. My guess is that some larger percentage are owned by women who defer claims of ownership to their husbands so the total number of gun owners might be higher than 60 million. I know that 50% of all households possess a firearm of some sort. That means about half of all adults can easily lay their hands on a firearm stored somewhere around the house.
Firearm is a pretty broad term including handguns, shotguns, rimfire rifles, muzzleloaders and centerfire rifles.
In 2001 there were about 13,000,000 active hunters in the United States. Ten million or so were deer hunters. I haven't seen data since then. Here is the address library.fws.gov/nat_survey2001_deerhunting.pdf . Really interesting stuff. I was surprised by the number of hunters who use primitive weapons. Bows or muzzleloaders or both. Of course, most of the primitive weapon hunters also hunt during rifle season. Some of them use their primitive weapon. I am going hunting this year with a guy who has decided to leave his 270 behind. He is using his muzzleloader instead. He says he finds hunting with his 270 too easy. For many really avid deer hunters the firearm is secondary to the hunt. Instead of a second deer rifle they are probably plunking down serious money on a bow or a deer stand or maybe a muzzleloader. You only use a centerfire a week or two a year. A bow or a muzzleloader extends the season. If you want evidence of just how popular archery and muzzleloader hunting is, just watch the outdoor channel. Every other show seems to feature a bow or black powder hunter.
Some percentage of the 10,000,000 use a shotgun instead of a centerfire rifle. They are mostly Eastern hunters.
Anyway I am still looking for statistics indicating the number of centerfire rifles in America, but I bet it is a smaller percentage of the 300,000,000 firearms in America than the percentage of shotguns, handguns or rimfire rifles. I haven't found the statistics proving or disproving either of our arguments yet. They are both in play, but I have to tell you I still think that there are a lot fewer owners of multiple deer rifles than you think but I am now pretty sure that the number is higher than I originally thought.