The progressives have one goal, total confiscation of all privately owned firearms, except maybe for their personal security details. Any compromise on things like "assault" weapons, mag sizes etc, takes us one step closer to their goal.
We are all aware that something like >60% of the U.S. public favors some kind of meaningful, uniform , and effective gun control. (I doubt 60% of the population would describe themselves as progressive.) I'm guessing that only a fairly small minority want '...total confiscation of all privately owned firearms, except maybe for their personal security details.'
If your premise is wrong, and I am not saying it is, then it wouldn't necessarily follow that Any compromise on things like "assault" weapons, mag sizes etc, takes us one step closer to their goal.' It seems possible that somewhat effective, uniform gun control, i.e., something more effective and more uniform than we have now, might make our right to own firearms more secure rather than less. Something to think about anyway.
https://www.google.com/search?q=what+percent+of+Americans+want+gun+control&ie=utf-8&oe=utf-8
My impression is that few want private gun ownership made illegal, but a large majority want private ownership of certain kinds of guns, and certain kinds of ammunition and clips, viz., the kinds
unnecessary for hunting, sport, or personal defense to be illegal. Many of us have pointed out that making the types of firearms useful for killing many people in a short time illegal won't keep these firearms out of the hands of criminals. I think everyone understands
that. What it will do though is make it more difficult for criminals to acquire them, easier to spot, and easier to apprehend before they use them to commit a crime. Over a period of decades the number of these types of unnecessary firearms in criminal hands would be likely to decrease, but no reasonable person expects the number to drop to zero. No reasonable person expects an end to all gun violence, all gun crimes, and all mass shootings. Most people understand intuitively that the best they can hope for is a reduction in the rate of incidences.