This ban on high capacity magazines does seem unreasonable. Hopefully it can be successfully challenged.
WHAT EXACTLY ARE WE PLANNING?
1) Legal challenges to the bans on so-called "large capacity magazines" and "assault weapons", as well as to the most egregious aspects of the new ammunition restrictions.
2) Monitoring CA DOJ’s proposed regulations implementing the new laws and challenging any improper ones in court.
3) Continuing to grow the grassroots structure that was created during the election year in counties across the state, which will allow for more influence at the local and state levels of government.
https://www.nraila.org/articles/20161216/california-doj-proposes-emergency-regulations-regarding-magazines-capable-of-holding-more-than-10-rounds-but-none-for-assault-weapons