got a simmons 30mm on my M4..doesnt work to well. the dot washed out at 100meters..meaning i could barely see it. had it on the highest setting and the dot filled up the who bulleye. looking at a weaver style Kobra or Cmore site. according to Cmore..standard cmore red dot site comes with 6Moa at 100 meters..thats awfully big isnt it? cdnninvestments has both. need more info, thanks guys.