The M14 is fun to take apart and put back together...you can talk to it too while you do it while watching full metal jacket....lol..just kidding.
Seriously, if thats what you want, get one..you most likely will not be dissapointed. Yeah a .22 is cheaper to feed but lots of guys learned how to shoot at a young age with .308 and .303.....before the 22 craze as previously mentioned.
I learned young on a .303 sporter,thats all I had access to. I was about 10...and the first semi I shot and learned to shoot was a FNC1A1 when I was 12 in cadets (when they had a better shooting program) I wasn't a big kid and with the proper instruction, me and all the others were fine with it.
IMHO, learning how to handle the firearm is the most important part...and it won't matter if its a .22 or a .308, If you aren't taught proper technique/fundementals and apply them, nothing will work for you.
I am buying my third Norc M14 when back (I am overseas right now), and had no problems with my first two (still have them) A few of my good friends got into the M14 thing as well, all norcs and no issues. Make sure, like I mentioned you learn how to shoot properly (if you don't know already, that is)...I have seen so many people blame the gun when it is their technique and failure to apply basic fundementals that is the issue, and you hear about it on here all the time as well.
As for accurizing....noramal strippping and assembly and maintanacne won't ruin that but....fire the thing bone stock first, then you can start to accurize and imrove the rifle as needed...you may not need to do any work on it at all.
Anyway, hope this helps....the Norc M14s are a blast to shoot...a real fun rifle for the range, plinking, competition and hunting. Send me a PM if you require any tips on the shoooting thing...I have a background in shooting instruction in the Military and Police service and have helped guys from CGN in the past from simple tips to hands on practical coaching and instruction....just do it via pm, I am out of the country right now and check CGN every few days and PMs are easy to spot.
Hope you get more into this sport...its a blast...pun intended.