9mm duplex loading

Any information concerning these 9x19mm cartridges with the duplex bullets and the sub-sonic loading ? This box is about twenty years old ?

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regrettably, everything i know about that combo is hearsay. that said:
what i was told was that sog groups in 'nam, and also tunnel rats , were issued modified browning hi-powers with an ammunition fitting that spec. one of two people who told me this was a confirmed tunnel rat with two tours as such.
it was used on dogs and sentries , was said to be inaccurate as hell at over 10 meters, and was used in conjunction with a 'wet' [grease-filled] suppressor.
i was also told that it did not last long [time indeterminate] in issue before it was withdrawn and replaced with single slug subsonics again, with improved suppressors and a slightly hotter load.
since then, a wide variety of companies have offered duplex configurations for use in battle-rifles , and in the competitions for enhanced defense options for support personnel. a quick search on the defense update sites will give you some of those. i'm pretty sure 'olin' had a duplex product range along with their 'telescoped' ammunition offering, but i may be remembering wrong....

---------- Post added at 08:17 PM ---------- Previous post was at 08:08 PM ----------

i've just been reminded by an old 'guard pal that the last go-round for a battle-rifle and a support-personnel defense weapon did indeed include a 9mm duplex round loaded submachinegun , that tests were run about twenty-odd years ago at a number of bases , by at least two military branches; and that fort devens mass. was one of the various test ranges used...
apparently a truckload of ammo was supplied, and only the weapons were taken away after the tests. your box wouldn't happen to have "kind of generic markings on a white or dark green box depending on ammo and maker" would it?:lol:

i did find this:
Ammunition for Armor-Testing NATO 9mm x 19

they list a duplex ammo for nato testing..
this is interesting:
Ammunition Cross Sections

and it also just occurred to me you might have meant a duplex powder load, in which case you're on your own!:lol: