AO-27 was a Soviet fully automatic assault rifle, chambered for the 7.62 mm fin-stabilized flechette sabot round. The flechette itself had a body diameter of 3 mm. The overall length of the round was 63 mm, and the flechette 55 mm. The weight of the round was 10.5 grams, with 2.4 grams the weight of the flechette.