The Walther P5 is the sidearm of James Bond (Roger Moore) in this film, despite having told Q that he "mislaid my PPK". The P5's use was to appease Walther, who wanted to promote the new pistol. Interesting to note is that the P5 was the same pistol used by Sean Connery in Never Say Never Again, the rival film version of Bond released the same year as Octopussy.
Walther PPK
The Walther PPK does make a brief appearance in the film, being held by a gloved hand in front of the woman during the title sequence. It is never featured during the film itself though.
Astra Cub
During the attack on Kamal Khan's palace, Octopussy (Maud Adams) pulls a nickel-plated Astra Cub, but is knocked out of her hand by Gobinda (Kabir Bedi). An Astra is also held by a woman in the title sequence.
Colt M1911A1
In the film's opening, one of the Latin American military soldiers flashes a M1911A1 when he takes Bond into custody.
Colt Python
One of the U.S. Air Force Security police guards manning the gate at the West German U.S.Air Force base carries a Colt Python, which he draws on Bond when he attempts to enter with the German Police hot on his tail after stealing the car he is in. Because of the many civilians milling around, the guard is forced to fire his six shots into the air, to alert his comrades to the security threat.
Makarov PM
One of the women in the title sequence is seen holding a Makarov PM as the "007" logo is emitted in laser beams.
Octopussy (Maud Adams) takes a Smith & Wesson Model 36 from one of the Air Force officers at the circus and uses it to blow the lock off the base of the circus cannon, revealing the atomic bomb inside.
Rifles
Fake M16 Rifle
During the precredits sequence in the unknown Latin American country, the soldiers all wield Japanese MGC M16 replica rifles with 20 round magazines. The soldiers guarding James Bond (Roger Moore) after his capture are armed with M16s, after Bond pulls their parachute ripcords, commandeers one and uses it to shoot out the truck's left front tire, causing it to crash (it then becomes a blank-firing M16 for that part).
SKS rifle
Several Soviet soldiers and some of Kamal Khan's guards can be seen with SKS rifles.
AKM/AKMS
AKM and AKMS rifles are used by virtually all of the Soviet soldiers in the movie.
Oddly, carbine versions of the Steyr AUGs are used by a few Soviet soldiers in the movie. This is likely the earliest appearance of the Steyr AUG in a Hollywood film.
AK-47
The East German border guards use milled-receiver AK-47s.
SA Vz. 58
The SA Vz.58 is used by some of Kamal's men, and Bond (most notably while sliding down the banister).