I don't think that it would be legal for SR in either NRA or CMP matches. At a local club match you might get away with it, but at a sanctioned 50 round or 80 round regional XTC if someone noticed you would get tossed into the Match Rifle scores. Since they were never part of a service rifle they would be verboten. It took 10 years after they were issued for the flat-topped AR receivers to become SR legal.Just read the NRA service rifle rules above. I have an Uncle Mikes removable sling swivel on my M1A so I can attach a bi-pod. Does that disqualify that rifle for CMP or NRA service rifle matches? I didn't see anything in the NRA rules regarding the sling swivels. Have not read the CMP rules yet. Any thoughts on this? Thank you.