Re: A2 Carry Handle
For CMP/highpower, you would be okay with back up style sights under certain conditions:
1. The rear would almost certainly have to be of the type I showed before:
http://rockriverarms.com/index.cfm?fuseaction=category.display&category_id=320
Supporting windage and up to 600y elevation in MOA-based increments. You could use a hooded sight with something like this. You also should not be removing it from the upper once a zero is established.
2. The front sight would have to be one that locks *solidly* in the up position, similar to the YHM ones. Also, once in the up position, I would advise against putting it back down, but I think there's much less risk for zero shifting than by full removal.
3. The front sight would have to support standard A2-style front posts that could be lowered and elevated. This is so that you can set the proper zero (say 100y) with your rear at its mech. zero. It's also so that you can use thinner or thicker posts at your discretion.
I've done something very similar to all this, which is how I know it works. For all these reasons and from my own considerations, I again advise something like this:
http://www.amazon.com/AR-15-Scope-Mount-Weaver-Rail/dp/B000FX305O
atop a standard A3 carry handle. It gives you every benefit- your irons remain locked in place for highpower, you have a relatively QD mount for your optic, and you can use the sights *with* the optic still attached. It's much, much, MUCH easier to rezero a slightly off optic when you're blasting for fun than it is rezeroing irons, especially in any type of match setting.
Besides, it was good enough for Sarah Connor