The first thing that would change would be every tactical bobo with a 2" AR barrel scrambling to buy a 18.5" or longer barrel or barreled upper along with every other person scrambling to try to find a longer barrel so they could go shoot their rifle in the woods. The shortage/sold out websites will be almost instant.
And then me strolling out into the woods whistling the same day with my 20" A1 AR15 to go shoot paper

lolol
In all seriousness though, nothing changes. Just that I can finally go shoot my favorite rifle at paper targets on crown land much more frequently and score one more point toward common sense/logical firearms laws in general in this country.