Dev, I dunno man. I've been using BAC ACOGs now for close to three years I'd say. I've used them in a lot of different environments. Light, dark, inside, outside, sunny, raining, daytime, night time, very close quarters, all the way out to 450 yards. The only time I had trouble with the BAC was when I first got it. I dont know what you mean by having to lower the rifle. I've never once had to do something like that. So long as I keep both eyes open, the unmagnified view stays in focus.
As you know, the way BAC works when you are moving around in fast paced, fluid shooting is because the magnified view is too blurry and out of focus for your brain. Therefore it ignores that image and concentrates on the unmagnified view. Think about it, in close quarters, the magnification of ACOGs makes targets and objects that are very close quite blurry. This is because they are too close to really focus on. I believe this is why I have never had a problem with BAC in close quarters. The magnified image of the walls and objects that are so close to you are never in a tight focus through the ACOG. They are too close. Therefore, for me, the unmagnified view remains constant for me.
I just ran around my place 3 times clearing rooms to confirm this. I tried moving quickly, I tried moving slowly. I tried it in lit rooms, I tried it in dark rooms. I tried it from lit room to dark rooms and the other way around. I tried it in dark rooms with no light, I tried it in dark rooms with the Surefire. I tried it with the Sirefire and blue filter, I tried it without the filter. And like I said, I never once had a problem with the magnified image distracting me.
Interestingly enough, just for kicks, on my last run of the place, when coming out of the bedroom and into the living room, I was facing my glass patio door. At that point, I searched from inside through the window to the outsie. From there I can see whats got to be a clear 300 yards out to the main street. When I came out, looked out the window, the magnified view took over. Im telling you, I love this thing.
One thing I do know is that when using the BAC, I never look "into" the scope. I never look at the reticle. I am always looking at the target area. So long as I do this, the little red donut just floats around in the unmagnified view. If I were to try and focus on the donut, things would get blurry and confusing. Thats the trouble I had when I first got it. I was trying to look into the scope, at the reticle. Once I stopped that and focused on the target area, everything started to fall into place.
The only thing I have to be aware of is my head position behind the optic. Because of the shorter eye relief on the TA31 I am using, you have to more or less keep your head locked in behind the glass. Not 100% locked in, you do have "some" room to play with, but head position on the TA31 is more critical than say a TA11 or 1.5X or 2X Compact ACOG. And *A LOT* more critical than with something like my Aimpoint.
Again, nothing is perfect, but sheesh, the TA31 sure as heck comes close. I'll deal with the tighter head position to gain all the other advantages this thing offers! As always, YMMV.