The inability to articulate a need for guns like the AR that makes sense outside the choir will erode support for such ownership.
I agree, the process began quite some time ago, and is ongoing.
There is no rational argument that will open a closed mind. Experience, however can. The old saying "there is no more staunch law & order advocate than a liberal who has been mugged" is not entirely untrue.
I always have an issue when anyone frames the question as a matter of "need".
"Why do you need xxx....???" (an AR, or anything, really)
My first response is to think, "Why do I have to justify my "needs" to you?"
Which always leads me to the other related questions like "what makes you the arbiter of what I need? "why do you think things that YOU think I don't need should be banned by law?" etc, and usually devolves down to "who died and made you GOD???"
Most of the time, that all stays in my head, but there are times I am very tempted to say it aloud to them... Especially the arrogant ones. If they aren't arrogant (indicative of an already closed mind) and are actually trying to understand, just using the phrasing they have heard so many times, I do try and explain, in principle. I usually use something they can understand. Personal liberty, defense against tyranny, these are things that are abstract to most of them, and while they hear the words, they don't understand the meanings.
I like to use money as an example. Nearly all of them understand (to a degree) money.
Why do you need an AR?
Why do you need more than minimum wage??
That's different!
Is it?? How???
My money doesn't kill anyone!
NEITHER DOES MY AR!!
or some variation on that theme. It does a couple of things, first is that it puts things on a personal level. Second, if they can see it, it points out how someone else deciding what you need is not always the good thing they think it is. They're fine with someone else (them) deciding what I need, when it comes to guns, but not fine with it when someone else (I) decide what they need when it comes to something they care about (in this case, their money).
doesn't always work, of course, but once in a while, some of them do seem to get it. That it is the same principle at work, and they realize that it's NOT the right thing to do, when its directed at something they care about.