Don't get all tangled up in the two groove barrel business. They were just as accurate as four (or six) groove barrels with military ammunition in military rifles.
I am in no way doubting your claim, I am just curious if you have any proof or sources. Ive just been reading up a little on them, and it seems the A1, as issued to Marine snipers, were more accurate over the A4s. Any reason for this?