That said, I submit that you are wrong.
I admit that any regulation will only present a challenge to the gun nuttery that passes as the current firearms industry. There's always a workaround that will be exploited. No matter what is done with legislation the use of guns for killing innocent people will continue. That is what lead me to the conclusion that because we can't eliminate the carnage we should change our approach and reduce it.
There are problems with your approach, i.e. limiting magazine capacity. It can't be done. In states have limited capacity laws contraband magazines come from states without such limits. Were such limits made national there are numerous 3d printing applications available on-line. Nutters would simply print their own.
As for high capacity fixed magazines I can live with a 15 or 30 round fixed magazine loaded through the breach ala any of my WW1 and WWII infantry rifles. Knowing how long it takes to load those 5 and 6 round rifles I'd estimate that to re-load 30 rounds the same way might take a fella's lunch hour. Even with stripper clips it's not easy and doing so under pressure, say with 20 kindergarten kids screaming in your ear, will be difficult.
So, given the historic ability of the gun industry to find workarounds, I submit that the only solution is to ban the two functions that make it possible fire 500 rounds in 5 minutes in an elementary school: semi auto fire and interchangeable magazines.
Oh, BTW, I am a former FFL holder who can still put 3 rounds through a playing card at 100 yards with iron sights. I submit that I have an "adequate understanding of firearms".