.303 diameter black plastic cartridge


Case length: 2.395"
Neck diameter: 0.335"
Shoulder diameter: 0.420"
Base (magnetic): 0.465"
Rim: 0.470"

Any ideas? Joe


It is a 30-06 blank by SMI. Not the Italian one but the:
Suedsteirische Metalindustrie GmbH
There are headstamped (only the year) and unheadstamped versions.



obsolete posting as Rene was faster


That’s what I was wondering at first but base is larger by about 1mm and shoulder is 2mm narrower. Also the case length is 3mm shorter on the black plastic round. If I compare to standard 06 the shoulder angles seem quite different. I have 4 other 30-06 / M1906 plastic blanks, and they are fairly exact to a standard round. It does go in a 30-06 check die, but is 2mm short on headspace. I wonder why they made them so short with a fat base. Maybe the fat base seals the round better but how is it going to chamber and extract being 2mm short on headspace?



I fed it to my Springfield 1903A3 and the extractor just pushed it forward in the chamber so that I had to push it out with a cleaning rod to retrieve it. There is no way the firing pin would reach the primer. I looked it up according to what René said in Chris’s book 30-06 and he also claims they made some shorter that are extremely rare but that no packaging has ever been found to confirm designation. I am still skeptical. Maybe they made a special weapon with short chamber that would only take these blanks?? I do believe the manufacturer is as you guys state.


Joe, in Austria a model of this SMI blank with normal dimensions was adopted under designation “7.62 mm Knall-Patrone/MG A4” and made for M1919A4 (MG A4) machine guns; because of this I assume that its design was conceived only taking in account compatibility with its firing mechanism (i.e. not for rifles). I believe that these later export blanks with non-standard dimensions would be improved designs to facilitate feeding and extraction. Regards, Fede.


Fede, Thanks for the information as I have a 1919A4 and see how it would function just fine with the proper booster.