That is some mighty fine shooting!
I just tossed a DPMS A3 flat top upper with a DPMS carry handle attached on to my DPMS lower. My first shots were at a clay pigeon at 25 yards....No sight adjustments at all and I was right on target with the supplied post sight. I was also able to hit a 12" metal plate about 50% or 60% of the time @ 200 yards.
I like the post just fine but it's not great for precision open sight shooting. So I ordered up one of these.....
http://www.midwayusa.com/product/498...-reticle-matte
I still need to get out and sight it in but having used this type of sight before I know that it works like a charm.....