Call the townsfolk to arms in CA and you'll get people carrying a thousand different ARs all in various stages of FUBAR.
Some won't have detachable magazines and might load from the top or might load from the bottom like that LWRC, some will be single shot straight pull, some will have the curved dildo stocks, some with bullet buttons. What ever authority is unfortunate enough to be placed in charge of logistics and training for all that will prolly go insane. If they don't just turn tail and run like New Orleans.
If the apocalypse hits the land of fruits and nuts it could make for an interesting case study.
Back during the war for independence from England the American militiamen were at a disadvantage vs red coat regulars because their personal rifles could not mount bayonets like the British issued muskets. After the first volley the militia had to either withdraw or fight at a disadvantage with knives and tomahawks.
With those experiences still fresh in the minds of the writers of the Bill of Rights, it makes perfect sense for 'well regulated' to mean a certain minimum standard to ensure interoperability with the standard infantry weapon of the day. The communists have perverted the meaning to ensure nothing is compatible with nothing.
Go back to the era of Napoleonic tactics. A skilled musketeer can fire maybe twice a minute. A rifle is even slower to reload. Engagement ranges were short, 70-100 yards for good hit probability.
When your firearm is empty and the enemy is charging would you rather have a 17" blade mounted on the end of a 5ft gun or a 6" knife?
The red coats would be coming in a line formation too, so without a bayonet you're basically facing down a wall of spears... with a hatchet/knife.
Not very good odds. Make more sense now?
The American commanders would pull the militia sharpshooters out of the close fighting because they'd get slaughtered due to their hunting rifles not having bayonet mounts. It was better to withdraw and save them for sniping British officers since they were ill equipped to handle bayonet charges.
In the modern age a suitable militia rifle should at the very least fire semi-automatically and take a detachable USGI magazine. The more interchangeable parts they share with the standard issue infantry weapon, the better. That's my take on what "well-regulated" means = within military regulations. And these Kalifornia laws are exactly the opposite, they make all these rifles irregular with all manner of different parts just to be legal.