I was never aware soldiers (of any sort) might be equipped so.
These guys are on the frontline, so to speak, entering the conflict area. I can see strap-on weapons to get to the battlefront (parachute drops, obviously, for one), but when else is such outfitting SOP?
Or are they merely backpacking their stuff in and they will re-prepare later?
Also, as long as someone probably knows, what is the armament used?
Bearing in mind all the furore about fake news, it mak be worth mentioning that the Daily Mail (aka Daily Fail) got two important facts wrong.
He did not have a shotgun, it was a small calibre pellet gun. He failed to wrest the police officer’s gun from her, but instead threatened her with his own gun.
Those? Those are submachine guns that are seem to strapped across the chest with a really tight sling, probably with a snap release. I supposed it’s useful if you do a lot of climbing, but it’s a bit show-offy IMHO.
It looks like a short barreled H&K, a standard 9mm sub machine gun very handy for close quarters work. As for when they are armed like that, they are ***always ***armed liked that. I have never seen a SWAT team deployed without automatic weapons on at least some officers.
I am unclear about what the o.p. is referring to as a “strap-on weapon”, but in the case of a solidier or tactical weapon law enforcement carrying a carbine or submachinegun, the weapon is typically carried on a two or three point sling so as to allow use of both hands without having to set down (and therefore lose physical control of) the weapon. (You will occasionally see special tactics/forces team using single point slings, but this is more to just provide support and retention of the weapon during movement and they usually keep the weapon in hand during all operations.). I can’t get your video link to work, but a solider/officer might assist another in slinging a weapon to ensure that it is secured and isn’t caught on anything so it can be freed for later use.
I am guessing by a “leg strap-on” the o.p. means a holstered pistol. Virtually all armed police and special forces units carry pistols as a secondary or close quarters weapon, but the firepower, accuracy, and stability advantages of a well-designed submachinegun or carbine dictate their use in the circumstance that one expects to engage in armed conflict. A typical 4" barrel duty handgun chambered in a common full power pistol round like the 9mmP has an effective range of about 25 meters for aimed fire, and carries between 11 and 20 rounds of ammunition in the magazine, a sight radius of less than 6", and low profile “three dot” sights. A submachine gun like the H&K MP5 (also chambered in 9mmP) has an effective range of over 50 yards, has a 30 round magazine, and often has a forward grip, folding or fixed stock, a longer sight radius with more prominent ghost ring sights or optics and stabilizing strap, as well as the ability to mount a weapon light or other aiming aid, and so is a more effective weapon in a tactical situation. A short barreled AR15 pattern weapon (chambered in the more powerful 5.65 x 4mm NATO round) has an effective range of over 200 meters, carries between 20 and 30 rounds, will have tactical optic sights, full fixed or telescopic stock, and is the preferred weapon if actually expect to get in a fight between close range (over 10 m) and battlefield range (100+ m) combat. Such a weapon, however, is impractical to carry in daily use and practically impossible to conceal, hence why the vast majority of police and plainclothes officers, the majority of which never use a weapon in the line of duty for defensive purposes, carry combat or duty sized pistols.
It looks like the guys with an SMG on their back are the ones who are carrying equipment that takes up one or both hands like the riot shield or battering ram. Since they can’t use a two handed weapon while using the other equipment, and don’t want it hanging down getting in the way of the shield or ram, they have it on their backpack until they use it later.
And since nobody else has mentioned it, almost nobody carries actual machine guns. Those tend to be firmly mounted either on a stationary point or on a vehicle, and while some machine guns are technically man-portable, that’s only just barely, and they would still need a team to set them up on a mount of some sort before use. None are man-wieldable unless you’re a Hollywood character.
Submachine guns and assault rifles (which are man-wieldable, and often carried by SWAT teams and soldiers) are much smaller and less powerful than machine guns.
There are light machine guns (LMG) and squad automatic weapons (SAW) which are wieldable in a standing position by a single soldier or balanced on a bipod without a fixed mount. These are generally used for broad suppressive fire, and occasionally for concentrated or marking fire at the squad level. The generally require a second ammo carrier/loader since they quickly chew through more ammunition than a single gunner could feasibly carry, but they are readily man-portable. They would not be useful in any typical law enforcement application, and are rarely seen outside of front line light and medium infantry use owing to the logistics of using such a weapon, i.e. the need for regular resupply and maintenance.
It depends on which definition of ‘machine gun’ you use - the ATF (and US gun control laws in general) consider any gun that fires more than one bullet per trigger pull to be a machine gun, so SMGs and assault rifles definitely are machine guns in that sense of the term, but not in the military sense. Colloquially, people who aren’t especially interested in military terminology typically use the broader definition.