You need a cantilever ring set like Phil posted. The ocular of the scope should be about even with the rear of the receiver. That allows you to access the charging handle and the eye relief works when you shorten the stock.
You will never see the front sight tower with a scope turned up to 3-4 power. I have a 1-4 on one of mine and the crosshairs are dead centered on the front sight post on low power, kinda like a red dot. It makes acquiring the target faster.