Copyright International Ammunition Association, 2007. All rights reserved.
Cartridge of the Month April 2007
Italian 9mm AUPO self propelled/semi-caseless
Specimen and photos courtesy of Paul Smith
The 9mm AUPO round was designed to be used in the Benelli CB-M2 submachine gun [see note below for info onthe gun]. The ammunition was designed and manufactured by Fiocchi (i.e. Giulio Fiocchi, Lecco ; G.F.L.). The project dates from the early 1980’s. The ammunition is classed as a self-propelled ammunition which is made of brass. Upon firing, the whole round is propelled forward. Muzzle velocity (V10) is given as 390 m/s (1280 f/s). Note that this round is somewhat unique in using a side primer arrangement. There are only a couple of variations:
From left to right are illustrated the following:
1- Sectioned red base round; 2- Loaded red base round; 3- Fired red base round (the CB-M2 has 6 right hand grooves); 4- Loaded green base round; and 5- Dummy green base round (without green base). Priming compound pocket not formed.
Note the different design of the green base round. It has a slightly larger meplat and a longer forward parallel portion. It is not known what the design differences signify. The base of the rounds are sealed with either a waterproofed red or green paper cup. From the below drawing, note the position of the priming compound. The loose fine-grained propellant is held within the internal volume.
One of our IAA members has fired this gun. He reports it to be well made and very nice to shoot.
References: Paul Smith, Variations of Military Experimental Calibers
Benelli CB M2 Submachine Gun
From Wikipedia, the free encyclopedia (with corrections by Paul Smith)
The Benelli CB-M2 was a unique submachine gun resulting from a joint venture between Benelli and Fiocci, an ammunition manufacturer. The weapon itself was unremarkable, and operated by a simple blowback system, which is very common for submachine guns. The unusual aspect of the weapon was the round itself.
The weapon was chambered for the semi-caseless 9mm AUPO round. The AUPO was a much simpler system than the expensive and complicated advanced caseless round for the failed Heckler & Koch G11. The AUPO bullet had an elongated, hollow base that acted as the case. The propellent filled the hollow space, and was sealed into the bullet with a plug. Ejection was not necessary because the base which acts as a "case" followed the bullet down the barrel and exited at the muzzle, similar to a sabot. There were provisions for extracting and ejecting a misfired round, with ejection taking place through the bottom fo the gun.
The CB-M2 has never found any customers, and following the general demise of caseless ammunitions (after the failure of the German Heckler & Koch G11) the project was shelved forever. The CB-M2 never went into any scale of production and never passed the functional prototype stage.
Copyright 2007 by the International Ammunition Association, Inc. All rights reserved.
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Revised 31 March 2007