It has nothing to do with distance.
A DMM is assigned to a company or squad, his job is to stick with his team and provide cover.
A Sniper is a soldier with extremely advanced training in asymmetric warfare, survival, recon, intelligence gathering, surveillance, communication, navigation and psychological strength.
A Sniper works alone and his primary job is collecting information, not engaging the enemy. Snipers are only used to kill high value targets, commanders and general rank officers of the enemy.
They're used for sabotage ops, assassinations etc.
There is a HUGE difference between the two.
I don't think Indians are going to catch up with our Snipers anytime soon in terms of skill or dare i say, equipment.