NVM answered my own question.
"""""Brian Normandy is an instructor at Jackson Arms. “As long as we don’t have a detachable magazine in it, it’s actually a legal firearm,” Normandy said.
Other states allow people to use their finger to pop out the magazine and quickly reload. It’s called a detachable magazine, and in California, its use in combination with other features such as a telescoping stock or pistol grip is illegal.
The intent is to slow down the process of reloading the weapon. But many target shooters don’t like the reloading hassle. “For me to use this on the range, I would have to open up the receiver and top load it,” said Normandy.
To get around this, gun manufacturers are selling firearms to Californians with what is called a “bullet button.”
The user uses the tip of a bullet to release the empty magazine and pop in a new one. The button doesn’t work with one’s finger, so the magazine is considered “fixed.”""""""