Shutter sound and "feel" can vary from camera to camera. If it is a well used and serviced camera, over the decades they tend to get quieter and smoother. It also depends on the preferences of the technician. Some tend to set the springs hard (to ensure consistent speeds mainly), others can get them to move more "softly". I used to have a M3 that was overhauled by Rudy Ling in LA. This camera was the smoothest of them all - whisper quiet shutter and "hot knife through butter" advance.
My stash of M2's varies - one of the black ones is now leading the pack, almost as good as Rudy's M3. One of the chome ones, fairly recently serviced has a distinct "sprooing" to the shutter. probably needs a couple of 100 rolls to settle in.
The absolute champion for smooth and quiet operation, at the moment, are not M's! It is a black paint Nikon S3 Millenium - just a soft click, soft enough that you suspect that you did not take the shot - and a buttery smooth advance. The other two S3's are not nearly as smooth.
A good technician can adjust and lube them for this kind of performance - or you can keep shooting with it until it settles in.