I have gotten every nork M14 I have ever owned under 2 moa with very little effort. Getting them to 1 moa would require a lot of effort, but consider this:
At 500m, which is way further than most guys will ever shoot in real life, despite what they might tell you on the internet, a consistent 2 MOA gun will put EVERY ROUND within about 3 inches of a human heart.
At 750m, 95% of rounds aimed at center of mass would still be a lethal hit to vital organs - heart or lungs.
If you needed a DMR, a 2 MOA M14, which is very easy to build without interfering with reliability or creating a need for extremely particular ammo, would do the job better than 99% of shooters could appreciate.
I haven't been keeping up with it as a result of ammo cost, but I used to shoot my M14s regularly at 400m. They were extremely reliable and could produce very consistent results at that range.
On the internet, everybody talks about sub-MOA rifles, but in reality most factory ammo is not really good enough to do 1 MOA groups anyway, and it doesn't particularly matter, because a 2MOA rifle will still out shoot most guys past 200m anyway.
Unless your idea of a DMR rifle is a rifle to sit on a bench rest and look vaguely military while shooting tiny groups. For me it is a rough, rugged, reliable gun capable of lethal hits at a range beyond a typical carbine - say 250-750m.
I have no doubt that something like a KAC SR25 would be more accurate etc...but the M14 can still be a very effective DMR in my opinion.