New Cartridge of the Month posted


Go to the main IAA page and click on the link to Cartridge of the Month to see the entire series.
This month’s example is apparently the latest “new idea” of a “self contained cartridge” dating back to the “rocket ball” and the volcanics, and more recently the Gyrojets. I would like to show a family portrait of sectioned cartridges on some theme like that, or maybe the .22 rimfire family tree or something. Here is a chance for some of you specialists (with the skill and experience to do this stuff safely- everybody else don’t risk life or limb!) to show us some of your treasures.
THanks once again to Paul Smith for this one. We have a couple of others in line for coming months, but your submissions are always welcome. PM me for an email address to send photos and text.


No show or description of the primer.


Priming is in a belt about halfway down. I have no idea how it works, but would think that maybe the gun has some sort of firing pin that strikes the cartridge at that point from the side rather than the traditional longitudinal firing pin. I don’t even want to think about how they manage to get the priming compound in there. A strange cartridge indeed.


This round having ring primer inside bullet. On this picture you may see how this weapon had to works.

For me most interesting question is from what consumable plug (red or green) was done. From pressed propellant or from other material?


My fired round (red base originally) has a very clear firing pin mark about 0.110-0.112" below the shoulder, right where it should be according to the firearms mechanism drawing in Yuri’s nice posting. The firing pin mark is round, about 0.06" wide (as near as my old eyes can tell, and as steady as I can hold a digital caliber these days). There is a very long firing pin-drag mark below the firing pin indentation itself, in the shap of a long “V” making the entire firing pin mark, including the actual strike, 0.3515" long, with the top of the drag, naturally, being the same width as the diameter of the firing pin strike. another interesting think about the fired round in my AUPO collection is that, unlike the one in “Cartridge of the Month,” the bullet is not hardly deformed at all other than general scarring and rifling striations. Under a magnifying glass there is a tiny bit of deformation around the edge of the flat nose but not much. Must have been shot into something pretty soft. I don’t have the dummy green base round, but my red-base factory dummy has two holes in the case, and the red plug is present.


It appears that the primimg compound rests around the skirt on the base of the “bullet”. The headspacing on this thing had to be critical. My understanding is that the accuracy was not good.