9 x 19 Armour Piercing

Good evening every one,

I’m assuming this is a 9mm AP round but it’s correct designation/title I’m not sure or. Any info would be appreciated.

Head stamp is

12 - HP
3 - 6 pointed star
6 - 9mm
9 - 5 pointed star

Any help would be appreciated.

Bizarre design. I assume they must be made from a solid, long steel(?) rod which is knurled on a lathe, then cut off in lengths for each bullets?


Something is “wrong” here!

If that is indeed a full steel penetrator then it’s soft steel.
Normally barrel steel run around 42-48Rockwell and for the penetrator to not strip rifling it needs to be “way” softer and that kind of defies the purpose and design.
I know many calibers ran iron (clad) bullets but that is dead soft iron and not intended to be AP. The German WWII full iron bullets were sintered and therefore “pliable”
That being said the rule of thumb was/is that 3 iron clad lead bullets wear as much as 4 copper ones and for sintered the ratio is 1:2.

From Matt Collins’ book:

Chapter on American Ballistics, page 53, quote:

1 Like

Thanks Brian!


Many thanks for this additional information


John P

I think virtually everyone who has seen / picked up one of these or other variations they made using a solid steel bullet asked the same question.

Well 20 rounds down range, guess it’s time for a new barrel !

In the 1980s, a lab at Aberdeen fired a few of these rounds through a test barrel, measuring chamber pressure and MV, into a quarter inch plate of cold rolled steel (I have no idea of the actual identity of the steel). With the pointed ogive the fired bullet was embedded in the steel plate with just the tip showing out the back. This was an informal trial and not documented, but the chamber pressure on these rounds was very high. It may not have mattered how long the barrel would last since the pistol would not have much of a life in any case.

As mentioned above, a VERY special use cartridge.