Well, going by the answers you've given (and I acknowledge I may have misunderstood them), perhaps we could slightly reduce the fatality levels in mass shootings by restricting all but three types of gun:
1) Revolvers, which take a little longer and more effort to load repeatedly than magazine weapons
2) Rifles that load bullets directly into the stock
3) Shotguns and similar instruments that load from the rear
Going by that, an "assault weapon" might be any magazine-loaded weapon.
Would you support a retroactive ban on all weapons that do not fall under those three types? If not do you expect banning the sale of these weapons will eventually make a difference due to attrition of ownership? Or do you actually believe banning them now will make a meaningful difference now? Especially considering the extreme rarity of mass shootings in relation to all other types of gun violence.