Yep... taking a whack at it... 'cause the old way just ain't workin' any more...Licensing, registration, vigorous vetting, etc., WILL greatly reduce the number of weapons that mentally unstable folk and criminals are able to obtain openly.
This guy was not judged as mentally unstable, therefore your idea wouldn't' have worked. The Vegas shooter the same. He was not diagnosed as mentally anything and bought his weapons legally through the background check system.
The Bigger-Fish-to-Fry is the 29,900... and taking a whack at substantively reducing THAT number.
And that's all it would be too---just taking a whack at it. We don't need to turn the entire country upside down to "take a whack" at anything. We either have something that will stop all mass shootings or we don't. I don't want our representatives to keep making regulation after regulation, law after law, and all along making it more miserable for law abiding citizens to buy or own guns. You know it won't work, I know it won't work, and it's just a foot in the door for liberals to keep piling on more regulations. Because you'll demand X, and when we have another shooting, you'll demand another X, and another X.
I say no. Democrats cannot be trusted.