Look slike th ebigest gun is a 90mm - which is perfect for African conditions and even in situations such as Iraq - where the main opposition tanks are older russian tanks. The 90mm has some good penetration and will knock out or damage most tanks out there pretty badly. Add to this the Ratel's speed and manueverability, and it makes for quite a weapon against older targeting systems - which it was designed to do. South Africa never faced a modern army and probably never will - such is the nature of warfare in Africa. The most advance weapons we have are the rooivalk - which is up there as far as attack helos go. Here is some quoted text:
"The Ratel 20 IFV is a wheeled, infantry fighting vehicle designed in the early 1970s to circumvent the arms embargo of South Africa. The vehicle is equipped with a turret-mounted 20mm autocannon, a coaxial MG-4, another MG-4 (C), and yet another MG-4 pintle-mounted on the rear roof (manned by the infantry squad). Main entrance to the passenger compartment is via a large door on either side of the vehicle. There is also a driver’s hatch on the front deck, hatches for the commander and gunner on top of the turret, and eight hatches on the rear deck. There are four firing ports on each side that will accept any assault rifle or submachinegun. The Ratel 20 is used by South Africa and has been sold to undisclosed countries.
The Ratel 12.7 Command is a command version of the Ratel armored personnel carrier. The Ratel 12.7 has a two-man turret with an M-2HB, and a MAG in a mount on the rear roof. The command Ratel has three radios, a tape recorder with time injection, a combined receiver and cassette recorder, internal loudspeakers, a PA system, a pneumatic radio mast, and map boards.
The Ratel 60 is a wheeled infantry support vehicle designed in the early 1970s to circumvent the arms embargo of South Africa during apartheid. The vehicle is equipped with a turret-mounted 60mm Gun/Mortar, a coaxial MG-4, another MG-4 (C), and yet another pintle-mounted on the rear deck and manned by the infantry squad the Ratel 60 normally carries. Main entrance to the passenger compartment is via a large door on either side of the vehicle. There is also a driver’s hatch on the front deck, hatches for the commander and gunner on the turret deck, and eight hatches over the passenger compartment (four to a side of the deck). There are four firing ports on each side that will accept any assault rifle or submachinegun. The Ratel 60 is used by South Africa and has been sold to several undisclosed countries.
The Ratel 90 is a wheeled fire support vehicle designed in the mid-1970s to circumvent the arms embargo of South Africa during apartheid. The vehicle is equipped with a turret-mounted 90mm gun, a coaxial MG-4 (the South African-made version of the MAG), another MG-4 (C), and yet another MG-4 pintle-mounted on the rear deck. Main entrance to the passenger compartment (not normally used) is via a large door on either side of the vehicle. There is also a driver’s hatch on the front hull deck, hatches for the commander and gunner on top of the turret, and eight hatches on the rear deck for passengers. There are four firing ports on each side that will accept any assault rifle or submachinegun. The Ratel 90 is used by South Africa and has been sold to several undisclosed countries. "
from:
http://www.globalsecurity.org/military/world/rsa/ratel.htm