I want the laws dealing with guns to make sense.
It makes sense to require a background check every time you purchase a gun, perhaps even every time your purchase ammunition (if, for example, someone acquired a gun illegally or acquired one in another way that would not show up in any system..and needed ammo.).
That said, background checks need to be reasonable as well - a brief check of available records, if nothing odd shows up you are allowed to purchase the weapon and/or ammunition. If something questionable shows up, you have to wait while they check further.
Edit: In the background here are things I know little about - how good the interaction between local, state, and federal law enforcement is, how well record sharing works, if at all... Whether it is even possible, currently, to look up all available records and see if there is reason to dig deeper...
The intent and goal being, to prevent people who are or might be a threat from easily acquiring a weapon they can use to kill others - while at the same time allowing people who are just out to go hunting or target shooting to do so without unreasonable paperwork.
The main issue is not whether we need to have background checks, but how we determine who is "a potential threat" - who needs checked more closely. Without some way of restricting and/or monitoring the process that marks individuals as potential threats, it could be abused or mishandled.
And has been already, in some cases, if I understand the history of the current "no fly list".
For all I know, things already work this way in most cases of gun purchase - but it needs to be all cases.
On to the topic of capability restrictions - magazine capacity limits and banning of, or additional paperwork required for, certain weapons.
In some ways, it makes sense to limit the the types and maximum magazine capacity of weapons someone can purchase easily - but at the same time, I think there needs to be a provision (probably more in-depth background check, etc) allowing someone to purchase such things.
You can argue that magazine size and weapon type aren't really going to stop someone from killing people - and you'd be right. But it might at least slow them down a bit.
In the end, all laws of this type will do is make it more difficult for someone who is mentally ill to kill a bunch of people. Attacks like Orlando will still happen. We might be able to reduce them by improving mental healthcare and awareness, but that's an entirely different, if directly related, topic....I digress.
For myself, that is enough for me to support improved gun laws - but they must be done right.