You are confusing the stats. You can't talk about the total U.S. population with any of these numbers.
Rather, if you look at the subset of 30 states that report who is a registered Republican/Democrat, you can get a count for those states: 35.7 million R/45 million D. Also 32.5 Independent, but no mention of non-partisan or unaffiliated. It also does not include alllll the people who aren't registered. It also excludes all the folks who aren't letting anyone know they have a gun.
The statement is that "the party" "owns 90% of the guns"
It seems obvious that 100% of the guns would be all guns in the US. So the claim is that Republicans own 90% of the guns in the US.
I did make a mistake though- I counted gun owners. So my math would be flawed if per owner, Republicans owned more guns than non Republicans. The claim was about how many guns they own out of the total guns, not how many gun owners are Republican vs non Republican.
It's funny how it creeps up on you. As a die hard liberal, I never thought I'd own a gun, but then I moved to a problematic neighborhood with lots of drug dealing and random pit bulls running around so I bought one, felt good about using it and thought I was done.
When my grandfather and father passed away, I inherited their guns, so I got them cleaned up and in good working order. But then I started looking at "gaps".
For example, dad had this, an adorable, but useless .22 Derringer:
I love it because, well, it was my dads, but I'd never think of actually using it. But the Derringer form factor is a kick so I bought one of these:
Chambered for .45 but also takes .410 shotgun shells...
Then that got me thinking... "Wait, dad and grampa had all these guns but not one shotgun?"
So I bought a Mossberg Shockwave and fitted it with wood furniture.
So, yeah, after buying one and thinking I was done, I now own something like 14 guns?
I inherited a revolver that's kind of a family heirloom, but it's a gun and it works, so learned to shoot it. But it's not a daily driver, so I bought a 9mm to take to the range as well. Then I thought it was silly not to have a rifle as well.
So yeah. I feel you. I'm a liberal. I also live in a state that doesn't require registration, so I'm curious how I'd ever appear in these statistics.
Yeah, I don't know many people who end up with two guns and stop there. One gun? Maybe. After that, it gets like they need friends.
One of the silly 'tests' of what makes for a REAL Alaskan is to have more guns than mammals living in the house. My non-scientific casual survey concluded that to be fairly accurate, and would probably apply to several other of our more rural states as well (REAL Montanan, etc.). Side note: dog mushers keep their dogs outside, so the stat held for them, too.