SWAT Team Gun Tactics: Intimidating But Not Practical

I don't know about clearing the room with a long gun; a carbine maybe, but not a true target-rifle.

You have your contact team come in with firepower they can manipulate in tight spaces. Dude with a shotgun as caboose, to put slugs through obstacles and covering the flanks.

The long gun belongs at a distance, able to reach out and touch someone, without being tapped himself. If there is ANY danger of that, the shootist needs a babysitter to cover HIS flanks and check for counterfire, usually with an assault weapon.

At distance, you have two or more marksmen, each covering different designated exits, windows, etc. Now THOSE guys would be looking through their sights, and sweeping the edges of their target area, for signs of a possible shot developing. For instance, you are on a rooftop down the street. You are supposed to take a shot if the perp walks down a hallway of the building, where there are 3 windows letting you see into that hallway. You'd optimally focus on the center window, but keep looking left and right. A person (perp, hostage, or your team-mate; it could be anyone) coming to the hallway will cast a shadow along the wall. you'll see that shadow maybe a second or two before you have your ONE CHANCE at a clear shot. since it will take your brain a second to differentiate friend from foe, you'll be looking for as much lead-time as possible. In THAT ONE SCENARIO, scanning with a scope would be appropriate.

But yeah, when I am closing in on a buck loafing on the perimeter of a bedding area, I carry the gun at port arms, or a variation of it. A rifle is too heavy to carry for more than a minute sticking out in a firing position. I expect my target will be within 50 yards or so, and I might not use the scope at all.

If I was within 20 yd, I'd have my gun up and looking down the length of the barrel.

I also use a shotgun for pheasant with both eyes open; again, carrying the gun at port arms until I hear the thunder of wingbeats.

Aliensun
Ok, think about how a person can accurate throw a rock to hit a target. Hint: Rocks don’t come with sights.

Some military groups DO something sort of like that in CQC, there are two similar techniques for sidearms called point-shoot and the Israeli Method.

Point-shoot at close distances can be quite effective. But you wouldn't want to engage with point-shoot more than about 10 feet away.

eta: Shameless plug inserted here --> Aliensun, if you're interested in this sort of thing, you should check out your local IDPA chapter. Many of them will have some old Army fart such as myself teaching point-shoot for competition. There is also IPSC that is very similar in general but different in detail. If one or the other is near you, they're both good, and a nice change from shooting on a pistol range. Not that there's anything wrong with that.