
Personally, when I started shooting AR open sight, I shot with both the eyes open; without blinder. I still find it tough to shoot with a blinder on or through scope. With AP, I also started with both eyes open and without blinder till dyplopia forced me to eventually choose one eye over the other. So it was first the right eye followed by the left and now (once again) it's the right. Now I close the left while shooting but open it WIDE OPEN after lowering the AP to allow the LE to get all that light in as required. And I also now use the glasses off and on - with absolutely minimum change in the shot placement. Of course through all these experiments my skills slipped and rose only to slip and rise over and over like King Bruce's spider.

For serious target shooters, both with AR and AP, as FF2003 said, I too have observed most of them all use the blinders. May be that's an essential mantra that works. Must try that out sometime during this year.
Can not comment on combat situation since never been there. But methinks, by and large, when it comes to shooting with rifles, it can be divided into two parts - the major chunk would go to the "assault" phase where taking a careful and long-lasting aim and "slow" fire is close to redundant and the minor "sniper" phase where the shooter (sniper) is least bothered about the surrounding flashes or flares or even where the shot gets placed. It's the spotter who would guide him to his point of impact. In any event I do not think the sniper would keep shooting 40-60 shots staying at one place for long - that would be a dead giveaway. So he gets enough time to refocus and readjust his eyes. And my experience with "hunting" is primarily and only when with AP, I lose discipline of SOA and SA and then end up punching a #7 or even a #6 instead of a #9 or #10.
regs
A.