speaking of accuracy: are they on average capable of <5" at 100 yards? anything over that, IMO, is bordering on the unacceptable. what sortof accuracy should i expect?
are there any subtle methods of accurizing that dont involve an expensive rebarreling?
I had an opportunity to try one of my Norinco M14s about two/three months ago with a cheap bushnell scope atop of a B-Square mount. I'll have to apply some locktite to the mounts and rings before I try sighting it in again, but am happy to report that I was getting one inch groups at 50m before things started to come loose. From the range reports of others on the site, I'm pretty sure that you'd have to be very unlucky to find a rifle shooting 5" groups. I'd expect somewhere in the range of 2-3 inches, perhaps less with tailored reloads being able to reduce the groups further. (BTW, I'd also say to get a different scope mount, but that's another issue).
Rather than worrying about expensive modifications, I'd be more interested in fixing the timing on the barrels.....that is to say that when the Chinese screwed the barrels into the reciever, they weren't careful enough much of the time to ensure that the front sight was not tilted a bit to the left or the right. Further to requiring some really far out adjustments on the rear sight to centre the groups, even that basically works to centre the groupings only at the range at which you've sighted the rifle in. I believe that there's another area on the site that covers how to fix this issue. A secondary issue with bad timing is that it usually causes the handguard to come into contact with one side of the stock, while it shouldn't touch at all.
Aside from the timing, the best investment might be a National Match Op Rod Spring Guide, which costs about $40 plus shipping and taxes. Sometimes the rear sights don't work that well, in which case a USGI set (Garand sights work as well) might be called for. Rather than worrying about whether the rifle is safe or will be accurate, in my experience the timing issue is the only annoying attribute, since I haven't the tools to fix it myself and would like to shoot to 200 yards without worrying about where the rifle will print as a consequence. Otherwise I'd be thoroughly happy with her as she comes out of the box.
Despite the past criticisms of the M14S, there has developed a very loyal following of those rifles that made it into the US before the embargo. In addition to debunking much of both the "Fulton Armory" writeup on them and the infamous side by side comparison done by "Guns Magazine" (where they shot the rifle out of the box without cleaning the cosmo off, and dunked the rifle into a barrel of water once the cosmoline caught fire), there seem to be no shortage of Americans willing to pay $800 for a like new Polytech or Norinco.