4 mm CETME Projects


As with the 3 mm caliber rounds, these spanish cartridge projects of 4 mm caliber were also designed by CETME around 1972 and never gone beyond the drawing board.

    • Project No. 1: 4 x 31,2 mm
    • Project No. 2: 4 x 27,2 mm (different from final 4 x 27 mm cartridge)
    • Project No. 3: 4 x 22,3 mm
    • Project No. 4: 4 x 23,45 mm
    • 4 x 31 SR (Günther Voss Patent projectile)
    • 4 x 22 mm (Günther Voss Patent projectile)



Fantastic drawings! That 4 x 22.3mm looks like one of the recent “short magnum” rounds in small scale… Don’t think I have seen the use of volumetric descriptions on cartridge drawings before. That level of detail and the fact they never went past the design stage makes those ripe for a modern solid model rendering to “bring them to life”.

Thanks again for the great drawings you have been sharing.

Anyone interested in seeing “virtual versions” of Fede’s drawings?



Yes, please!



Here is the “Project No.3” 4 x 22.3mm as shown in Fede’s drawing next to a .303 British for scale. Little bitty thing…

And in a different scale…

The model is complete per the drawing. Very quick to build with all the detailed dimensions! We can get creative with a headstamp if there is any idea what it should be.

Edited to add section view.



Dave, wonderful model!

The 4 x 27 mm CETME produced cartridges bear no headstamp or 4C SBT 74.


Thank you, Dave, incredible!



These are the 4 CETME my collection.



Thanks for showing those examples of what I assume are the 4x27mm “final” cartridges Fede mentioned. Could you further describe or display the first image of what looks like a very flat pointed projectile? Would not seem to be a champion contender in the ballistic coefficient competition!

Here’s the final installment on the 4mm project…


  1. Are the angled vent holes for Berdan priming common? Would think that would make for a much more complicated case forming process.

  2. Are the 4.44mm and 3.30mm primer diameters used elsewhere or are these special to this project?

  3. Note the #4 Item has no anvil shown as typically used on Berdan primed cases. Intended for a Boxer primer perhaps? Then why no central flash hole and typical dual flash holes for Berdan priming?

Hope the models are of interest and if anyone would like a particular view or combination shown, feel free to drop me a PM.


Edited to show final group photo and add question on Item #4.


See final group image above.