Steel case .303?


Was .303 British ever made with a steel case? How about aluminum?



When I had my .303 collection, I had two different aluminum-cased .303s, both British and both unheadstamped. I never had or have seen a steel-cased .303 (other than solid dummies), but I certainly would not be willing to state they were never made. One of my Aluminum-cased .303’s had a reinforced head and primer pocket of another silver-colored metal, but it did not take a magnet. That one was actually half an empty case - it had been section full-length and I had only one the one side. Frankly, it was more interesting than a complete case because you could see the sectioning. Still, I guess I would have preferred a full case. The other was all aluminum.


The .303-producing community was rather limited. Off-hand I can’t think of any .303 producers that did any significant small-arms ammo work with steel cases. Did I leave any steel case makers out?


The Only major users/makers of .303 which had steel case-making facilities were the Italians and the Japanese. As both these nations used the .303 purely for Aircraft MG use, Brass was the material of choice…even the Germans used steel ONLY for ground guns, Luftwaffe ammo being made of Brass, or occasionally copper coated steel (small lots). This was to do with reliability of extraction in high altitude (and Cold).

Both Italy and Japan used steel in ground based ammo, but only well into the war, when copper was in short supply for making brass. I have not heard of any .303 (Italian or Japanese) made with steel cases.

The British made all their .303 from Brass ( as did other Commonwealth nations) as during WW II, all or almost all British .303 was made to Air Service Standards.

Nowadays, with Russian Ammo plants making steel cased western calibre ammo (Wolf .223 and .308 etc) it is possible if they get into making .303 for the American market, that it will be steel cased as well… we will wait and see.

Regards, Doc AV
AV Ballistics.


Aerators Ltd & the Royal Laboratory made experimental steels cases during WW1. Kynoch made some during WW2. Results (some burst cases) and ample brass supplies did not warrant full-scale production.
Aluminium cases were made by Greenwood & Batley (2 piece case) and also by Radway Green & Kynoch after WW2. RG & K cases were anodised whole range of colours. I have plain alu .303 Mk 6 allegedly made by British Aluminium - but I suspect they were metal suppliers and Kynoch actually made them. There is a Mk 7 version also - have no info on dates made.


As John P-C says, there were several attempts to make steel cases at different times, together with aluminium cases.

I was told many years ago that the Mark VI and Mark VII alloy cases were actually made by Birmingham Metals & Munitions before WWI (which would explain the Mark VI) but I cannot verify this. I am sure John is right about British Aluminium supplying the metal.

Here are some examples, all unheadstamped.

L. to R.

Steel case - unknown
Aluminium - unknown
Aluminium - Birmingham? as above
Aluminium - unknown
Aluminium 2 piece - Greenwood & Batley 1930s
Aluminium 2 piece - Greenwood & Batley 1930s

L. to R.

7.92 Besa Aluminium RG or Kynoch 1948
Nos 2,3 and 4 are the same rounds as previous photo
Nos 5 to 8 are all from the 1947/48 light alloy case trials and made by Kynoch or RG.


What was the earliest Steel case smokeless cartridge



What a stunning collection of .303’s


Well, im speachless. I had never even seen a decent colour photo of one.
And now that. They would make a superb display lined up in one of MY cabinets. Very nice TonyE


O that they were all mine.

Some of the rounds are from my collection but the pretty coloured ones belonged to another collector and the picture was taken for reference purposes.

The whole alloy case project from 1945 to 1948 is of great interest to me. I also have

.280 natural colour waxed aluminium
.280 orange anodised
.280/30 orange anodised
9mmP orange anodised

I have had natural coloured 9mmP by Kynoch ( but Lew had that!) and a 20mm Hispano bright orange headstamped RG 48 P. I also know of a .270 orange anodised round.

If anyone can add to that list I would be grateful.



I almost had a blue anodized .280!