I bought two of the Tasco red dots with the variable dot size. They are the PDP3 and PDP5CMP. The PDP5CMP has 4, 8,12, and 16 MOA dots and it currently resides on my 3.5" Mossberg 12 ga. It was on my 41 magnum Redhawk. The smaller scope was on my Ruger 10/22, but was removed because it covered a squirrels head at 50yds making it hard to make good head shots. For quick shooting they're hard to beat, even on a shotgun. For accurate shooting go with a conventional scope with some type of duplex or fine crosshairs. To me(this is strictly my opinion, worth whatever you get out of it /ubbthreads/images/graemlins/confused1.gif) a rifle with a 1 MOA dot will never shoot less than 1 MOA on a regular basis. There just isn't as good a point of reference. My PDP3 only stayed on my AR for about 15 minutes until I realized that it didn't have the 100yd potential a scope had. If I was going red dot on a rifle then the smallest possible would be the answer.