sacramento calif. california senate thursday pass sweep package gun control bill would require background check ammunition purchasers ban possession high-capacity magazines establish firearms violence research center bill whose passage assembly far assure heart political duel senate leader kevin de leon lieutenant governor gavin newsom democrats propose compete plan advance key election campaign gun violence reach epidemic proportion across nation de leon represent los angeles say introduce bill senate floor thursday stand communities suffer horrific violence package eight bill would ban possession ammunition magazines hold 10 round make steal gun felony limit lend gun among family members close loophole state assault weapons ban uncertain whether bill pass assembly republicans conservative democrats block measure past sign democratic governor jerry brown veto gun control measure senate bill fast-tracked legislature week even state officials count signatures prepare place november ballot referendum newsom would accomplish many goals compete measure sore point two powerful politicians could spill november election campaign well race replace brown 2018. de leon say thursday newsom base ballot initiative de leon proposals ask lieutenant governor agree withdraw ballot measure senate bill pass newsom run governor refuse campaign strategist dan newman say thursday initiative comprehensive legislative package go voters fall newsom expect make gun control initiative centerpiece campaign replace brown 2018 along propose referendum legalize recreational use marijuana de leon endorse newsom close possible newsom rival governor race include former los angeles mayor antonio villaraigosa california senate pass gun control package