Without going through the NFA process you are not getting an M14 but
Springfield Armory will sell you an M1A Semi Auto version of the M14.
I paid $600 for mine but that was over 30 years ago. I think they are
more like $1600 now. These are accurized versions of the GI model,
made for people shooting "high power". You can also buy a chinese
knockoff a lot cheaper and they are not horrible if you get one with
the better quality bolt. There were problems with the earlier ones.
You can get a USGI bolt but it may need to be fitted into the receiver
by a gunsmith,
I got the "carbine" thing out of my system with my Ruger 44 mag. I
would like a box magazine for it but I don't shoot it often enough to
make it a problem.
Why would you want a 9 pound rifle?
For shooting high power ammo. If you do not have to carry it all day, that
weight and physics makes for more enjoyable shooting. We shot M1 carbine
in USAF training. Nice low power rifle. I had a Ruger 30 carbine revolver
years ago. Only firearm I got rid of. Friend wanted it and I did a 3 way
trade for a Colt 357. The pistol was the 3rd loudest pistol in existence
at the time, early 1970.