there is no simplistic answer to this. any recognizable manuf is a contender and
you'll need to consider size, weight, attenuation, etc. but also, bear in mind
that using a semi-auto as the platform isn't the best choice...too many clickety
clacking and whooshing going on. but as long as you accept the drawbacks
then i guess you'll be happy with less than full rifle bark. you may also want to
head over to Uzitalk and Silencertest (both, dot com) to see and ask others who
may have outfitted similarly.