My only hunting experience with a silencer is limited to my CZ .22. The silencer works well with subsonic ammunition (a bit quieter than an airgun), but if you fire CCI Minimags its just as loud as having no silencer. The silencer I have is threaded onto the barrel & is around 6 inches long, and made up of a tube with a series of washers & springs.
I have seen a Ruger Mini 14 with a suppressor the whole length of the barrel. They guy that owned it told me he didn't use subsonic ammunition & it was similar in loudness to a .22 lr.
I use my CZ .22 with silencer firing winchester subsonic hollowpoints for head shooting goats out to about 50 yards. Drops them every time.