Need Information on Olin 9mm L Subsonic ammo

I saw an interesting can of 9mm ammo at a gun show yesterday. Sorry, no camera with me but here are the particulars.

The can was a standard .50 cal olive drab GI type stencilled with the same information as the boxes contained inside. Each 50 round buff colored box was marked:

Cal 9mm L (subsonic)
WCC87 H030-002
N00 164-87-C-0202
Olin Corporation

The cartridges were headstamped 9mm L WCC 87

The interesting thing to me was the bullets were all jacketed hollow points, obviously a bit unusual for Military packaged ammo. Was this for Special OPs? Or just military style packaging for a Federal Law Enforcement contract? I also didn’t recognize the significance of the “L” in the designation. Is that related to the subsonic loading or something else?

It was a full can of 1000 rounds but a bit pricey for shooting ammo and I don’t have an MP-5-SD to feed anyway. But I’d like to know more about the ammo. Thanks.


The ammunition was for special operations personnel. There is no international prohibition against the use of expanding hollow-point ammunition against terrorists and other non-uniformed personnel of which I am aware. It is prohibited for use against regular, uniformed militqary forces. this was discussed on an earlier forum, and should not be confused with non-expanding HP bullets. The NAVY Seals regularly acquire HP pistol-caliber ammunition, as far as I know. Despite having been in the Army, I don’t know about Army, Air Force or Marine Corps special operations folks.
I simply knew a chap, another cowboy shooter, that was a Navy Seal.

The “L” was originally thought, by people out of the military loop like me, to mean Luger, the commercial appellation of the cartridge, but actually is the code letter representing subsonic ammunition. I don’t know the history of why the “L” was selected for that purpose. Some early Federal Subsonice ammunition had an “S” on the headstamp.

Lew can probably fill us in on that. I really should have just let him answer this anyway. He has forgotten more about this caliber than I will ever know.

I don’t know why the change was made from “S” to “L”. One of the very many things I do not know about cartridges, and particularly 9mmP.

Is “L” used on other calibers or by other countries to identify subsonic loads? I have seen it on IVI headstamps, but I suspect these were for a US contract. I don’t recall any other examples.

The use of the “L” for subsonic was not confined to Olin Industries. It must have been mandated by the military or whoever had authority over this particular ammunition procurement. You will note the the earlier, top box pictures uses just the “SUBSONIC” designation. The headstamp on the cartridges from Lt FC-89E001-002A is “FC 89 9MM S” while that on the lower box, which simply calls the same basic loading “CAL 9MM L” and is lot FC-92A001-018" bears the headstamp “FC 91 9MM L”. Seems like it is still another detail that bears more investigation.

Collection of John Moss

Thanks again for all the great info!