Is this true?

Ok well heres the rumor
A buddy of mine has a friend who owns a para ordnance handgun. My buddy was able to put a couple of rounds through it, he says that it was so loud he couldn't hear. This I can understand, but than the kid whos handgun it was said that the noise is about the same as a suppressed M4. This I just can't take myself to believe. My friend told me to get some proof that the M4 was quieter so I am coming to you guys. Whats the real truth here?
Chris