S_Baker...
Our room clearing doctrine USED to be, "Throw grenade, wait for blast, then spray inside"... but they‘ve changed it now.
Apparently one reason for the change is that if you throw a nade in first, in most cases you will get injured as not all houses are made like the ones in fibua sites (interior walls of brick/stone). Also, the potential for civilian casualties, etc.
So, this summer, without a PAM, they taught us the drill on our BIQ course. It was very ad-hoc, as there actually wasn‘t supposed to be any fibua training in our shortened BIQ course. We entered a room in teams of two, splitting the room in half and basically doing a "door kick" entry, one going one way, the other going the other way, staying against the wall and looking very SWAT while having the rifle at the ready, looking for targets. They also told us to call out things like, "Window, left" or "Mousehole, Low Right", and "Two enemy dead" before shouting "Room clear".
BOOMER004... there is a whole school of thought (they are called "old timers") who think the 5.56mm is a useless plinking round. The main reason why NATO - or at least the UK - switched from 7.62mm to 5.56mm, is because of the Bloody Sunday massacre, when British troops fired on armed republican insurgents in Northern Ireland, and civilians who were in the area and even those not in the area were killed by overpenetrating 7.62mm rounds, which had gone through walls, etc. At the time, the Brits were using the FN‘s.
Other reasons of economy no doubt led to the adoption of the 5.56mm, all of which have been discussed to death (you can carry more, etc).
I think Stoner or Armalite make an M16 variant in 7.62mm, and it sounds like it would probably be a great service rifle. But the "plinking" round will be with us for the forseeable future, I would think.