FWIW, I have a couple M7 Bayonets and they are certainly lighter then the M9 but I think as a survival knife the M9 bayonet is better tool. The M7 is certainly a better bayonet.
I am looking for anyone that knows the history of the M7 to help compile that M7 history...
http://www.m7bayonet.com/
I would love to get some help to compile info like Bill and other helped do for:
http://www.m9bayonet.com/
Yea, the sites look pretty similar