The " Arms ( Military Style Semi-automatic Firearms and Import Controls ) Amendment Act 2012 " aimed to clarify the MSSA definition in regards to Airsoft and Paintball guns , as well as magazine capacities . Amendment summary : Intended effect : On the 15th of March , 2019 , Australian national Brenton Tarrant opened fire in two mosques in Christchurch , killing 51 people and injuring many more . The shooter used legally-obtained semi-automatic weapons , which he had illegally modified after purchase . Following this attack , gun law reforms were announced almost immediately , and at 3 pm on the 21st of March many semi-automatic rifles and shotguns were reclassified as Military Style Semi-Automatics thus requiring an E endorsement to own them . Such guns must be confirmed by an act of parliament before 30 June 2020 or they will be revoked . A gun buyback will be offered
opened fire in two mosques in Christchurch
Christchurch mosque shootings
Military-style semi-automatic firearms