Chinese 7.62x25 Subsonic

I acquired one of those Chinese 7.62x25 Subsonic rounds. I have a few questions about it.

The characteristics are: Bimetal steel/copper case headstamped “11 88” with brass coloured primer cap. Brass coloured pointed FMJ bullet which is very strongly magnetic.

What is the proper designation of the round?

Was the bullet designed especially for this cartridge?

Also, I have forgotten the name of the silenced SMG it was designed for.

Thanks for any info.

Type 64, both the Cartridge and the Silenced Sub Gun, from my visit to Beijing in 1996 and firing one at the Beijing Friendship Range ( along with a Type 95, an SGM, and several other firearms).

The only sound was the barely audible"clak-clak" of the miniaturised AK Turnbolt mechanism ( Closed bolt firing).