It is often pronounced "kosh", but in German the "ch" would sound like the "ch" in Scottish "loch".
Further information: The name is German in origin and is actually correctly pronounced with a hard h. The final phoneme of 'ch' should not be pronounced as a ck, nor is it a 'soft' h. It is a unique and distinct hard hsound. The vowel is a short o like in the word hot.However, like many German names, it has been anglicised in some regions so that various individuals with this family name may pronounce it as cook, cock, koch and so on.
The Wikipedia entry for Heckler & Koch is not strictly correct. It gives the pronunciation as: hÉ›klÉʔʊntˈkÉ”x. Explanation for the "ch" (transliterated as "x") part is as follows:
xBach
loch (Scottish)
Koh or Kok(if you're referring to the name of the doctor/biologist who discovered the tuberculosis bacillus).
Eik Koch's birth name is Eik Koch Snchen.
Ed Koch's birth name is Koch, Edward Irving.
Garrison Koch's birth name is Garrison Anthony Koch.
Jay Koch's birth name is Julius Koch Jr..
Ralf Koch's birth name is Ralf Karl Koch.
Rod Koch's birth name is Rodney Allen Koch.
Beate Koch was born in 1967.
Heinrich Koch's birth name is Heinrich Georg Koch.
The word 'koch' is not Swedish, but German. Koch means 'cook' or 'chef' in German.
Federico Koch's birth name is Federico Ral Koch Valenzuela.
Hawk Koch's birth name is Howard Winchel Koch Jr..