Military Guns and Ammunition

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This is intended for people interested in the subject of military guns and their ammunition, with emphasis on automatic weapons.

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30X136 HS825 - Information    Aircraft Guns

Started 15-Jun by paolog75; 458 views.

From: paolog75


Dear All 

First of all thank you in advance for the help. 

I'm new on the forum, so let's introduce me, I'm from Italy and I'm an aviation fan. 

Recently with some friend have started to collect documentation concerning an Italian jet made in the 50' called Aerfer Sagittario 2 and it's derivate the Aerfer Ariete. 

Since the production was limited to just few airframe, the documentation is very little, So we are sorry to disturb you but we have some need of information concerning the ammunition used by the gun installed, the HS 825, which was also a prototype. 

On the base of reserve done, we find some study made by Mr. Anthony G Williams that bring me here.

We have also checked the book “Rapid Fire The Development Of Automatic Cannon, Heavy Machine Guns And Their Ammunition For Armies, Navies And Air Forces” and other web site, but we cannot find any other bullet than the practice HE in 30X136. It seems that the only ammunition made in this caliber was the TP (practice shooting) HE (explosive), and perhaps also the instruction cartridge, so basically only ammunition for Air TO Air activity.

We are interested to know if the HS 825 could have also AP belts, or any other type of since a version of such plane was also intended for close air support as light fighter bomber, ad to colelct as much information possible on the gun itself and the ammunition. 

Thank you again for the help. 



From: autogun


Welcome Paolo,

These are extracts from my forthcoming book, Autocannon:

30MM HS 825: 30 × 136 and 30 × 136B AMMUNITION.
This gun and its ammunition were specifically designed at the beginning of the 1950s for aerial combat, the goal being to combine a high hit probability with the substantial destructive effect needed to destroy jet aircraft, in a compact and light weapon. This was achieved by selecting the 30mm calibre but with lightweight projectiles to enable very high muzzle velocities to be achieved; the light projectile would lose velocity quickly at ground level, but not at the high altitudes at which future aerial combat was expected to take place. This was an efficient solution to the problem: the rival ADEN/ DEFA 30mm guns fired heavier shells but at much lower velocities.

The gun used a version of the usual Hispano-Suiza gas-delayed blowback mechanism. The gun barrel and breech body assemblies recoiled within the receiver, which was rigidly attached to whatever structure it was mounted to. The belt feed was driven by this recoil movement. The mechanism was tuned to achieve the highest possible rate of fire; however, the mechanism was working at the limit of its capabilities which resulted in unacceptable reliability despite much development work. It failed to get into service, although it was considered and frequently tested by the British Fleet Air Arm and was selected for the abortive

Swiss P16 ground-attack jet (an ironical choice, given the ammunition’s optimisation for high-altitude use). The gun was also initially planned as the armament for the Swedish SAAB 29D fighter aircraft, with four guns in the fuselage. However, problems with propellant gas building up in automatic fire and igniting every few rounds were not resolved, and neither the HS 825 nor the 29D model were adopted.

With a short L/53 barrel the gun was 238cm long overall and weighed 105kg. An L/70 barrel was also offered, increasing the overall length to 288cm and the weight to 112kg. The RoF was 950–1,000rpm and the belt feed could be to either side of the gun. Two different mounting cradles were available, one being fixed and the other allowing adjustments to be made in azimuth and elevation.


The case is a bottlenecked type. Early production rounds, as made in the UK, have a rimless brass case, but later Swiss-made ones have a belted steel case. Overall length is 209mm and the round weight is c.600g. The loadings were optimized for high-altitude performance against aircraft, featuring a relatively light 225g HE shell fired at the high velocity of 1,050m/s.


From: paolog75


Thank you so much!!!!!

I see that only Air to Air ammunition have been developed at the time. this match with the primary roles of the Aerfer Sagitario 2, that was designed to intercept heavy bombers. 

I would like to return the favor by sharing some basic information on the two airplanes mentioned, with the hope that you can add some short notes to your book on the illustration of the HS 825 cannon

HS 825 with the 70 barrel equipped also the Aerfer Sagittario 2 and the Aerfer Ariete, if you like I can share with you some documents, for the time here some prompt wiki reference

Due to the particular design of the plane (the jet engine was positioned in the frontal part of the airframe), it was possible to mount two HS 825 with a total of 240 rounds (2 X 120) positioned soon behind the cockpit.

Both planes, also if very interesting and capable were cancelled since F-86 were given for free to the Air Force and Nato cancelled financial support to the project for political reason.

By the way Sagittario 2 was the first Italian plane to overpass Mach 1. 


From: autogun


Thanks for the information!