It's interesting to see this widespread assumption. When you encounter a contradiction - check the premise. Which is in this case that (1) there will be a way to confiscate illegal firearms. And (2) that law enforcement officers will be willing to suffer innumerable casualties among their ranks.
Frankly, these two assumptions are batshit. crazy. There has never been a successful national cofiscation in even the most tightly controlled countries like France under Nazi control. And remember the American Revolution began when the British marched on Concord to confiscate the guns stored there.
Also, anyone who knows law eforcement officers knows they want to go home at the end of the day. Yet just making traffice stops gets some officers killed in the line of duty.
Gun ownership is already entrenched in the United States. In nations where it's not - we see mass shootings of the voluntarily disarmed populace every time some terrorist with a gun shows up and starts shooting.
Gun ownership CAN'T be infringed. Chew on this before perpetuating the idea that it can be infringed.