Dialing scopes typically have LOTS of erector assembly movement. You can't get 120 MOA of movement in a 1" or 30mm tube. The specialty ELR scopes have 40mm tubes! The more room inside the scope, the more the scope can move. The parts (lots of them are in fact copper alloys) are bigger and heavier. ED glass is VERY dense, bigger internal lenses= heavy. Thicker, stronger main tubes to keep the scope with all its inherent weight from deforming... It's a product of being big and strong.
