More on Halo 3: ODST. Pistola.

1. A pistol resembling the one from Halo 1 will be, according to Bungie, the primary weapon of choice in Halo 3: ODST.  Humans will be popping off headshots.  However, Bungie has also said that the Halo 1 pistol  was “ridiculous” indicating that it will some what be toned down.
2. The H3:ODST pistol is called a M6C/SOCOM.  The pistol from H1 was an M6D.  Bungie says you’ll be able to pick enemies off at a distance but that it packs a serious punch up close.
3. You’re a human.  You’ll run slower and the enemies will appear larger.  You’re no longer 8-foot tall wearing special armor.
4. No dual wielding or equipment.
5. New health system. When you get hurt, you’ll have to go find a health kiosk or soldiers in the field.
6. Don’t expect to be able to play as aggressive against the covies as you did as MC. 
7. Firefight co-op mode is pretty much like the Horde mode in Gears of War 2.
8. ODST's will have a low light vision mode toggled by the “X” button.
9. You’ll carry a PDA that gives you situational awareness. Access it through the “Back” button.

Info about Halo’s Pistols:

The M6C/SOCOM variant has an integrated sound suppressor.

Official Designation: M6 PDWS (Personal Defense Weapon System)

Common Slang Terms: Go-mag, cannon, hand cannon, power drill, HE pistol, heavy pistol

Cartridge: 12.7mm x 40 SAP-HE (semi-armor-piercing, high-explosive)

Max. effective range: 50m

Mag. capacity: 8 rounds (6, 12 in some models)

Rate of fire: DAO

Unit cost: 1615 cR.

Dimensions:

• Length o/a: 22.86 cm (9 in.) standard

• 26.7 cm (10.5 in.) 'up-sized'

• Weight (loaded/12 rnds): 1.8 kg (4.09 lbs) standard

• 2.7 kg (5.95 lbs) 'up-sized'

Variants:

• M6A: standard issue/black polymer finish

• M6B: 'Officer's model'—issued with smart-linked scope [KFA-2]/hard chrome finish

• M6C: 'up-sized', standard issue/black polymer finish

• M6C/SOCOM: accurized—issued with smart-linked scope [VnSLS/V 6E]/black polymer finish

• M6D: 'up-sized', 'Officer's model'—issued with smart-linked scope [KFA-2]/hard chrome finish

• M6E: standard issue/electroless nickel finish

• M6F: 'Officer's model'—issued with smart-linked scope [KFA-2]/electroless nickel finish

• M6G: 'up-sized', standard issue/electroless nickel finish

• M6H: 'up-sized', 'Officer's model'—issued with smart-linked scope [KFA-2]/electroless nickel finish

• M6I: select-fire variant; detachable shoulder-stock/black polymer finish

• M6J/C: carbine variant; 355mm barrel, detachable shoulder-stock/electroless nickel finish

• M6K: police 'undercover' variant; 6 rnd magazine capacity/black polymer finish

Developer walk-thrus: