Question: what is the benefit of a fluted barrel
[{'answer': 'to reduce weight', 'provenance': [{'wikipedia_id': '27739226', 'title': 'Fluting (firearms)', 'start_paragraph_id': 3, 'start_character': 31, 'end_paragraph_id': 3, 'end_character': 47, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'increase rigidity for a given total weight'}, {'provenance': [{'wikipedia_id': '27739226', 'title': 'Fluting (firearms)', 'start_paragraph_id': 3, 'start_character': 0, 'end_paragraph_id': 3, 'end_character': 422, 'bleu_score': 0.940033794885305, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 3052263720445038799}, 'section': 'Section::::Abstract.'}]}]