With the arrival of Terminator: The Sarah Connor Chronicles on British TV screens, it's clearly time to consider just how to deal with murderous and very determined androids from the future.

This might look easier than our previous movie-based challenge, "How To Stop A 500-foot Monster" (and its sequel), but the rules are a bit different. With giant monsters, you can count on the authorities to wheel out the F-18s and Abrams tanks pronto. When a Terminator kicks down your door at 2 a.m., it's just you and whatever you have on hand. While a 120-mm M829A1 round might swiftly convert a Terminator into scrap metal, I don’t believe that even DR readers keep a suitable cannon in the house.

Generally speaking, Terminators appear to be able to shrug off small-arms fire. However, as a military technology enthusiast, you have to ask exactly how good their protection is. Body armor is classified in several levels, roughly as follows:

Type I – .22 long rifle and low-velocity .380 – small stuff

Type II – stops 9mm handgun and .357 rounds – most standard handguns

Type IIIA – stop all 9mm (including submachine guns like that "Uzi, nine millimeter") and .44 Magnum – i.e., pretty much any normal handgun

Type III – stops the standard 7.62mm and 5.56mm rifle bullets used by police and military

Type IV – stops some armor-piercing rounds :"This armor protects against .30 caliber armor piercing (AP) bullets (U.S. military designation M2 AP), with nominal masses of 10.8 g (166 gr), impacting at a minimum velocity of 869 m/s (2850 ft/s) or less ... Type IV body armor provides the highest level of protection currently available."

A detailed technical breakdown is provided here.

Even if Terminators are equal to Class IV, they are well outmatched by modern ammunition: something like the U.S. military 7.62mm M993 round will defeat 15mm Type IV armor and punch holes though 15mm of steel plate. If that's still not enough and you want to "get bigger guns," something in .50 caliber might do. Barrett's M82A1weighs about 30 pounds, but with armor-piercing rounds it can go through at least 20 mm of steel, moving us into the league of anti-vehicle rather than anti-personnel weapons.

Incidentally, there's a clue in the first Terminator movie that you can take one down with standard firearms. When asked if he can stop it, Sgt. Reese replies, "Maybe. With these weapons ... I don't know." So perhaps he just needed the right ammunition.

If you do get through the armor, then one shot is unlikely to do it. Any combat robot should be designed with a high degree of redundancy and will have very few "vital spots." Unlike a human, it's not going to bleed to death, and the loss of limbs is not going to bother it. The Terminator films and TV series seem to bear this out; so keep shooting even after it goes down and make absolutely sure it's not going to get up again.

Of course, if armor-piercing ammunition will do the job, it's going to destroy most of that carefully constructed atmosphere of threat and fear that has been built up around the Terminator: "It doesn't feel pity, or remorse, or fear. And it absolutely will not stop, ever, until you are dead ... unless you empty a clip of M993s into it first, then it's history and we'll go for some beers."

One obvious feature of Terminators is that they have metallic armor, described as "hyperalloy." This is very much against the modern trend for body armor, which basically abandoned metal some time ago in favor of ceramic and composite combinations; they give much greater hardness and strength for the weight. The real reason for the Terminators' metal armor is probably that people equate robots with metal, and director

James Cameron says he liked the image of "a chrome-plated Death."

That chrome look means the Terminators' metal shell appears to stay shiny and unmarked whatever happens to it. There might be two possible explanations: extreme hardness or self-repair. Hyperalloy might be much harder than any known metal; this potentially makes it brittle, but highly suitable for armor. (Heavy tanks like the Abrams do have some fairly exotic heavy metal armor, but that's another story.)

Alternatively – and more entertainingly – there's the idea that Terminator metal might be some sort of shape memory alloy, capable of rapidly returning to its original form. This would explain why Terminators sometimes take a second or two to recover after being shot, while the memory alloy reverts back to shape. This could also lead to the development of the implausibly advanced memory alloys seen in later shapeshifting Terminators like the T-1000 and T-X.

(In addition, the shape memory alloy could explain why Terminators seem peculiarly susceptible to shotgun blasts, which have little penetrating power and can be defeated by light body armor. In Terminator mythology, shotguns seem to be the most effective weapon and knock the robots out of action for several seconds. Perhaps the impact force 'stuns' the robot, perhaps it causes larger deformation of the armor … or maybe Hollywood just likes pump-action shotguns.)

Being science fiction, hyperalloy does not need to obey the laws of physics. And the considerations of plot mean that Terminators shouldn’t really be vulnerable to small arms. So maybe we need something more serious such as a portable anti-armor weapon. While even the most basic

RPG-7will go through more than a foot of steel – surely more than enough – don’t use it indoors. In common with most rocket weapons, the backblast is highly dangerous; if used in a confined space it will convert you into toast.

If you're expecting Terminators in your living room, you want something with no backblast, such as the French Eryx or the new SMAW-D(CS). Unfortunately, the Eryx, like the RPG, has a warhead that does not arm until it is some distance from the launcher for safety reasons. So you'll have to get your Terminator to stand at least 50 meters away before letting fly.

The 40mm HEDP grenade is a much smaller warhead and more suitable for close quarters. Fired from most standard launchers, it can go through 2

inches of steel, and still do plenty of damage on the other side. But even this one arms 14 meters away – and causes (human) casualties in a 5-meter radius. Not quite the thing for indoor firefights.

Looks like this one needs a little more thought. There are lots of ways we can go ... Tasers, anyone? Proposals from major arms manufacturers and the fertile brains of DR readers are welcome.

UPDATE: Speaking of the Terminator, Boing Boing TV has an exclusive episode from the Sarah Connor Chronicles alternate reality game.