To be honest with you at 1x the difficulty of rapid target acquisition is equivalent to that of a micro red dot (in my honest opinion). I'm still fairly new to using low variable power scopes at <25 yards so we'll see if my opinion changes after a few more 3-gun matches. This scope does not have any rails built onto it however, you could purchase a 45 degree accessory rail mount considering how much rail space you have on you DD upper. You could also just purchase an M-Lok rail section and mount your red dot there as well. The advertised eye relief of this scope is 3.5". Below is a pic of how far back I have my scope mounted. From this point I adjust the buttstock to the point that I have my desired eye relief. @Michael88 in regards to AR15 gas length this is often what is sold on entry level AR15. Also, that's really cool that Brownells is an international company. It sucks that it takes so long for you guys to get stuff but at least you have the option of being able to obtain it. @David that revolver looks sweet.