Question: when was the 30 round m16 magazine introduced
[{'answer': '1969', 'provenance': [{'wikipedia_id': '19901', 'title': 'M16 rifle', 'start_paragraph_id': 2, 'start_character': 138, 'end_paragraph_id': 2, 'end_character': 142, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '19901', 'title': 'M16 rifle', 'start_paragraph_id': 3, 'start_character': 0, 'end_paragraph_id': 3, 'end_character': 517, 'bleu_score': 0.527645303611165, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 5017695607524883267}, 'section': 'Section::::Abstract.'}]}]