If you have a NM trigger, you are probably not following through properly and are bumping the trigger during recoil- that's a very common problem. Focus on riding the trigger through the recoil. If it's still double-tapping, have a 'smith look at your trigger group. Quite a few Springfield M1A's have cast trigger groups that are quite a bit softer than GI parts, and your engagement surfaces can wear very quickly. I had a NM M1A that this happened to. It got down to about 1/4 of what the engagement surfaces should have been, and the trigger pull dropped to about 2 lbs or less.