There's a world of difference between an M1 Garand and an M1 carbine.
The Garand shoots almost as well as an M14 but is less convenient to
load and reload.
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.