Battle Rifle BR55HB SR

Clip size: 36
max capacity: 144
rate of fire: ~6 rounds per second (3 round burst fire 2 burst/sec)
rounds to kill(body): 21
rounds to kill (head): 12
rounds before melee kill: 9
(same for head, no damage difference for headshots until shield is down.)
bullets before close frag nade kill(body): 6 (same for head)
bullets after close frag nade to kill(body): 5-6
bullets after close frag nade to kill(head): 1
bullets before far frag nade kill(body): ~12
bullets after far frag nade to kill(body): ~12
bullets after far frag nade to kill(head): ~3

NOTES: Accuracy at ranges more appropriate for a sniper rifle is so bad that aiming at the body may get you random headshots. Anywhere past the effective range of the weapon (where it begins to take more than 5 bursts to kill) aiming at the center of mass will many times be more effective then aiming for the head when attempting to get that final killing headshot. Aiming at the head, however, is always preferable when facing an unshielded opponent since headshots do more damage after the shield is down, but not before.

See the below saved films for demonstrations of the above:

Battle Rifle Spread Demo
Battle Rifle Range Demo
Battle Rifle Kill Demo