Table:
text: M16 rifle
Summary
Summary
Colt_model_no_ Military_designation Barrel_Length Barrel Handguard_type Buttstock_type Pistol_grip_type Lower_receiver_type Upper_receiver_type Rear_sight_type Front_sight_type Muzzle_device Forward_assist Case_deflector Bayonet_lug Trigger_pack
N/A M16A2E2 20 in (508mm) A2 profile (1:7 twist) Full-length semi-beavertail w/ HEL guide Retractable ACR ACR A2 Flattop with Colt rail None A2 ACR muzzle brake Yes Yes Yes Safe-Semi-Burst
646 M16A2E3/M16A3 20 in (508mm) A2 profile (1:7 twist) Full-length ribbed Fixed A2 A2 A2 A2 A2 A2 M16A2-style birdcage flash suppressor Yes Yes Yes Safe-Semi-Auto
655 M16A1 Special High Profile 20 in (508mm) HBAR profile (1:12 twist) Full-length triangular Fixed A1 A1 A1 A1 A1 A1 M16A1-style birdcage flash suppressor Yes No Yes Safe-Semi-Auto
656 M16A1 Special Low Profile 20 in (508mm) HBAR profile (1:12 twist) Full-length triangular Fixed A1 A1 A1 A1 with modified Weaver base Low Profile A1 Hooded A1 M16A1-style birdcage flash suppressor Yes No Yes Safe-Semi-Auto
945 M16A2E4/M16A4 20 in (508mm) A2 profile (1:7 twist) Full-length ribbed or KAC M5 RAS Fixed A2 A2 A2 Flattop with MIL-STD-1913 rail None A4 M16A2-style birdcage flash suppressor Yes Yes Yes Safe-Semi-Burst

Question: How many M16 rifle fall deflectors are there for Colt 646?

Question: What is the sight type on the model with the acr muzzle brake device on the M16 rifle?