funny mine runs just fine, is accurate and is MD legal like you asked. You must have gotten a Bad one or something to try out
15 M-14's ran through my hands. Best group I managed was 3" at 100 yards. I regularly shoot M193 in a 1.5 MOA ish circle. Different days, different conditions, all matchish ammo. (AKA not Tulammo or Wolf) M118LR or equivalent.
3" group was a very new Socom M1A 16" that I fired single shot (not by choice it was having feeding issues).