No silencer for old men
QUESTION In the film No Country For Old Men, the villain uses a shotgun with a silencer. Is this possible or was it just a movie prop?
In the 2007 movie no Country For Old Men, Anton Chigurh, memorably played by Javier Bardem, uses a sawn-off, Remington 11-87 semi-automatic 12gauge shotgun with a 10in suppressor/ sound moderator.
A suppressor is not a true silencer, but effectively reduces the blast of the shotgun to a soft ‘phut’.
the one used in the film wasn’t commercially available. It was made by Larry Zanoff, motion picture armourer at the Los Angeles prop supplier Independent Studio Services.
the only genuine suppressor available at the time was the hush Puppy, exclusively used for pump action shotguns.
however, the movie script called for a semi-automatic rifle so Zanoff set about creating one from scratch, figuring that Chigurh’s silencer would have a handmade look.
the sinister shotgun has become one of the most famous items in modern movies. the suppressor did not actually work — the sound of the shots was achieved through sound editing.
Ted Lewis, Wrexham.
A FIReARM silencer, more correctly called a sound moderator, slows and cools the pulse of propelling gas that follows the projectile from the weapon.
there are several designs, but usually a series of baffles are used, with a hole through which a bullet can pass with a small clearance around it.
A shotgun has a large diameter charge of shot that may be loosely contained, though modern cartridges contain the shot in a sort of cup.
there are three sources of noise from a gunshot: the escape of the propellant gas from the muzzle; the sound of the projectile through the air; and the ‘thump’ of the projectile hitting the target. the silencer only deals with the first of these. Ammunition intended for quiet use is designed to keep the velocity below the speed of sound compared to the ‘crack’ of supersonic bullets.
Most shotguns have long barrels — in the UK they can be more than 24 in — with large calibres. An effective silencer on such a gun would be very long and bulky, making it unwieldy.
however, there are silenced shotguns with a sleeve along the length of the barrel that are easier to handle.
In the UK, a silencer must be licensed. this used to be difficult to obtain but, today, given concerns about the effect on the shooter’s hearing and the need to control noise, sound moderators are readily approved by the police.
William Silvester, Weymouth, Dorset.
QUESTION With regard to vaccines, what was the Cutter incident?
In APRIL 1955, 200,000 children in the U.S. were vaccinated against polio using a defective vaccine. More than 40,000 developed polio symptoms, 200 were left with permanent paralysis and ten died.
the defective vaccine was supplied by Cutter Laboratories and resulted in the U.S. polio vaccination programme being put on hold while an investigation was carried out.
Cutter was found to be liable for breach of implied warranty, which opened a floodgate of litigation.
It also resulted in new legislation to protect vaccine manufacturers against lawsuits.
With the threat of litigation hanging over them, many companies were reluctant to produce vaccines, jeopardising immunisation programmes.
the Cutter incident resulted in better regulation of the production of vaccines in the U.S., making them among the safest in the world.
On the other hand, it left many Americans distrustful of mass vaccination programmes, a legacy that still exists in the anti-vaxxing movement.
Bob Cubitt, Northampton.
QUESTION How does the light on my car’s instrument panel know that a tyre needs inflating?
SInCe 2014, all cars have been fitted with a tyre pressure monitoring system (tPMS). It works via a sensor linked to the car’s computer, known as the electronic control unit (eCU).
there are two types of tyre pressure monitoring system: direct and indirect.
A direct tPMS is attached to the valve in the tyre. It works from a small independent battery that in time will run out and need replacing. this type is more reliable because it monitors the exact pressure within the tyre.
An indirect tPMS has sensors fitted inside the wheel, often alongside the anti-lock braking system. these detect tyre pressure as the wheel rotates.
As they can collect dirt from brake dust, they will need to be cleaned periodically.
When the tyre pressure falls to near 25 per cent below the manufacturer’s recommended pressure, the sensor in the tPMS sends an alert signal to the instrument panel via the car’s eCU.
this alert must not be ignored. In fact, it won’t switch off until the tyre pressure has been corrected.
Bob Thorpe, St Leonards-on-Sea, E. Sussex.
QUESTION Does anyone still have a pet rock?
FURtheR to the earlier answers, my pet rock was acquired in an unusual way. A colleague was going on holiday and I asked him to bring me back a seaside rock. On his return, he presented me with a large pebble from the beach.
this soon became known as Ricky the Rock after the workmate who had given it to me. It sat on my desk until I retired and is now used as a paperweight. A happy memory of my working days.
Helen Evans, Stroud, Gloucestershire.