Assimilation -gm- > -mm-

I am looking for examples of this kind of assimilation. The 'g' has
got to be a fricative, i.e. a 'gamma'. Whether the gamma in the
language you (hopefully) can provide examples from is a consonant,
semi-vowel or vowel is not important in this context.

I've found a man's name in Old Norse, Agmundr (Aghmunder), which has -
mm- already in Old Norse and quite frequently -mm- in modern
dialects. Old Irish has V:m from *gm as in 'ám' < *agmo- (*h2e-) (*g
in Old Irish is gamma, of course), but I don't know if one can tell
if this has gone through *amm-. Finally I've heard that Old Greek -gm-
has become -m- in Modern Greek, but they don't differ between old -
Vmm- and -V:m-, so that you can't tell what has happened there. Is
that true? What about 'Middle Greek' writings?

The examples don't have to be from IE languages, of course.

Sverre