I’m sorry, but the bullet in the picture has nothing to do with the 9 mm Kammerpatroner for the Swedish Kulsprutepistol 45, which are the cartridges described on the referenced web forum. That is a shiny, black-plastic bullet of relatively normal shape, and with none of the grooves or odd base shown in the picture on this thread. There is no lead in the bullet at all. Embedded in the nose is a steel ball, which is all that leaves the barrel of the special, tapered-bore barrel for the K’pist 45. The black plastic portion is pulverized and leaves the barrel as “plastic dust.” There is a red plastic equivalent without the steel ball in the tip. It is completely pulverized when fired in the correct special barrel, the same as for the gallery load, but with an additional muzzle constrictor.
Either of these loads (yes, the blank too) can cause serious injury to anything in front of the muzzle if fired in a normal barrel.
For collectors’ interest, I have a color reversal in each load in my own collection - that is, a black bullet without the steel ball (possibly a production glitch, but the next one makes me believe it is not), and a red bullet with the steel ball (which I do not think could possibly be a production error).
I suspect from my original source for these that they were something experimental, but I have no documentation for either of them, except to know that they are legitimate.
These rounds, by the way, are found usually with standard Swedish military headstamps, but are known with commercial Swedish headstamps and non-Swedish headstamps as well. I have a number of them like that in my own collection, and have seen others I don’t have in other collections.
I have no idea what the bullet pictured is, but from its length and shape, I have serious doubts as to whether it could be used loaded in a 9 mm Para caliber pistol or machine pistol with any success.
In passing, let me say that I have handled hundreds of rounds of the gallery load (and thousands of the blanks) and in the gallery load, I have never encountered a missing or loose steel ball from the plastic projectile.