| O/U Combination Gun |
- |
- |
- |
| O/U Shotgun |
- |
- |
- |
| O/U shotgun |
- |
- |
12 Gauge Double Barreled Shotgun |
| OA-93 |
- |
- |
Olympic Arms OA-93 |
| OF 37 hand grenade |
- |
- |
- |
| OICW |
- |
- |
Heckler & Koch XM29 Objective Individual Combat Weapon |
| OP-SKS |
- |
- |
SKS rifle |
| OP-SKS Rifle |
- |
- |
- |
| OSP-30 |
- |
- |
OSP-30 Flare Pistol |
| OSP-30 Flare Pistol |
- |
- |
- |
| OSS Pistol Glove |
- |
- |
Sedgley Fist Gun |
| OSSh-42 Flare Pistol |
- |
- |
- |
| Oberndorf Mauser Sporter |
- |
- |
Mauser Rifle Series |
| Oerlikon 20 mm Cannon |
- |
- |
Oerlikon 20mm Cannon |
| Oerlikon 20mm Cannon |
- |
- |
- |
| Olin Flare Gun |
- |
- |
- |
| Olympic Arms CAR-AR |
- |
- |
- |
| Olympic Arms K23B |
- |
- |
- |
| Olympic Arms K23B Tactical |
- |
- |
M16 rifle series |
| Olympic Arms K3B Carbine |
- |
- |
M16 rifle series |
| Olympic Arms K4B |
- |
- |
M16 rifle series |
| Olympic Arms M4 |
- |
- |
M16 rifle series |
| Olympic Arms OA-93 |
- |
- |
- |
| Ordnance SBML 2 inch Mortar |
- |
- |
- |
| Orion Flare Gun |
- |
- |
- |
| Orion flare gun |
- |
- |
Orion Flare Gun |
| Ortgies 6.35mm Pocket Pistol |
- |
- |
Ortgies Pocket Pistol |
| Ortgies Pocket Pistol |
- |
- |
- |
| Ottoman Musket |
- |
- |
Jezail Musket |
| Ottoman musket |
- |
- |
Jezail Musket |
| Over and Under Rifle/Shotgun |
- |
- |
- |
| Over and Under Shotgun |
- |
- |
12 Gauge Double Barreled Shotgun |
| Over and Under Shotgun (O/U) |
- |
- |
- |
| Over and under combination rifle/shotgun |
- |
- |
- |
| Over/Under Shotgun |
- |
- |
12 Gauge Double Barreled Shotgun |
| Owen Submachine Gun |
- |
- |
- |