The rise and sudden fall of the self-contained air cartridge system

Building a replica where the pellet and the compressed air are retained within the cartridge makes a lot of sense and in the 1990s, this was a popular approach. However, owning one of these replicas in the UK will now guarantee you a minimum five year prison sentence. How did that happen? Read on…

In the 1990s in the UK, slightly bonkers laws concerning CO2 powered replicas led to the development of a new type of airgun which used compressed air in a self-contained cartridge. These were hugely popular for around a decade until new laws outlawed them completely. Replicas using this system were beautifully made and functionally accurate, but this article is as much about media hype and the draconian laws it generated as about the replicas themselves.

I think most of us would agree that laws aren’t always well considered or logical and that laws regarding replica weapons are sometimes downright peculiar. But in the UK, these laws are positively byzantine and their creation has often been propelled by sensationalist and nonsensical reporting in the media as much as by any rational analysis of the issues. In the early 1990s, one of the targets of media frenzy in the UK were deadly airgun “super weapons” produced in Europe and the US. And what were these horrifying weapons of mass destruction? CO2 powered replicas! No-one seemed to particularly care that these guns were often actually less powerful than the pneumatic air guns that could already be legally purchased. I mean let’s face it, boring facts like that just get in the way of attention grabbing headlines about CO2-powered super guns.

Aren’t laws strange? In the early nineties in the UK the CO2 powered 250fps Crosman SA6 (left) was classed as a firearm while the pneumatic 450fps Weihrauch HW45 (right) could be legally purchased by anyone of 18 or over.

The outcome was that if you wanted to own a CO2 powered replica in the UK in the early nineties, you had to have a Fire Arms Certificate (FAC), not an especially easy thing to obtain. For this reason interest in CO2 powered guns was virtually zero in Britain at that time. In terms of UK law it was easy to single out CO2 powered guns for special attention. In the UK, an airgun is classed as a weapon which uses compressed air to fire a projectile. CO2 is not air, so these must be firearms, right?

One of the results of this slightly odd law was that in the UK some enterprising manufacturers tried to find ways to make realistic and powerful replica air pistols which used only compressed air. The unintended outcome was an even greater burst of media outrage directed at these new weapons and eventually the introduction of laws which outlawed them completely. Along the way, the previous vitriol aimed at CO2 weapons was quietly forgotten and in the late nineties these were accepted as air guns under UK law and their ownership without an FAC became legal. Some of the compressed air pistols produced during this period of media frenzy and legal manoeuvring were technically very interesting, especially those produced by Birmingham based Brocock Limited and it’s these I’m mainly going to talk about here.

Important note for readers in the UK: Before I talk in detail about replicas which use the Brocock BACS system, I want to make something absolutely clear:  Although these pistols were manufactured and legally sold in the UK up to January 2004 as air guns, they are now classed as Section 5 Firearms under UK law. This means that they are prohibited weapons and if you are found with one without an FAC or if you try to buy or import one you will end up spending a mandatory minimum of five years in prison and up to a maximum of ten years. Remember, that’s a mandatory minimum sentence so that five years is the shortest term to which you will be sentenced if you are found with one of these in the UK. So unless you really want the opportunity for a leisurely inspection of the inside of one of Her Majesty’s prisons, don’t do it. In fact, don’t even think about it. Sorry, but that’s just how it is. Welcome to the nanny state.

I believe that owning one of these replicas may still be legal in other countries including parts of Europe and the US but I would strongly suggest that anyone considering buying one should check all applicable local and national laws first. Right, having got all that scary stuff out of the way let’s actually talk about these replicas.

The Brocock BACS System

If you want to design a replica pistol which has maximum realism, there are lots of advantages to placing the power source and the projectile within a self-contained cartridge. After all, this is what firearms do and using this method allows maximum functional accuracy. In the 1980s, UK company Saxby-Palmer produced a number of replica air pistols and rifles which used self-contained air cartridges. However the system was cumbersome to use and in 1989 Saxby-Palmer went into liquidation. The rights to produce self-contained air cartridges were bought by the Silcock Brothers, trading as Brocock Limited in Birmingham. Brocock improved and perfected the Saxby-Palmer design and introduced replicas using the BACS (Brocock Air Cartridge System) in the early 1990s.

The Brocock system, also known generically as the Tandem Air Cartridge System (TACS), was as simple as it was ingenious. Each cartridge comprised two separate components (thus the “tandem” bit of the name). A machined brass air reservoir could be pressurised up to 3,000psi using the supplied hand pump. A .177” or .22”pellet was then inserted into the separate nose of the cartridge and this was screwed on to the front of the air reservoir. Where you would find the percussion cap on the base of a centrefire cartridge was the nose of a valve stem which released the pressure from the air reservoir into the nose, propelling the pellet. With the cartridge in the chamber, the firing pin of the pistol struck this stem when the hammer fell, opening the valve and allowing the replica to shoot.

Tandem air cartridges. Standard in .22” (left) and micro in .177” (right)

It was a beautifully simple system with very few moving parts and few seals. You did have to separately pump up the pressure in each cartridge before loading and achieving 3,000 psi on a single cartridge could take up to eight strokes with the hand pump. Charging all six cartridges for a Brocock BACS revolver provided the sort of aerobic workout most of us can only dream about (though it was also possible to charge the BACS cartridges using a SCUBA air tank). The pump was pressure limited so that it wasn’t possible to charge beyond 3,000 psi. The tandem air cartridges were said to be so well made that they would retain a charge for several weeks and pellets left the barrel at anything from 400 – 450psi depending on model.

Brocock BACS SAA

Brocock used this system to produce a number of revolver replicas in modern and Western styles and with various lengths of barrel as well as a small number of air rifles. They also made a single semi-auto replica, the Para ME9, which used a micro version of the tandem air cartridge and looked rather like a Walther PPK. All the Brocock BACS replicas were precision made and used quality engineering and finish and these air guns quickly became very popular in the UK. Other companies such as Uberti and Pietta also produced replicas which chambered BACS rounds. By 2002 an estimated 80,000 replicas using the BACS system had been sold in Britain alone.

Brocock Para ME9

Media frenzy

The Brocock BACS replicas were popular, well made and reliable and they weren’t excessively powerful, so you might wonder why they aren’t still around? The issue was that by the early 2000s, the UK media had transferred its attention from CO2 powered replicas to those which used the BACS system. It was claimed that it was simple to modify any BACS replica to use centerfire ammunition, essentially converting an airgun into a firearm. In an article in the Daily Telegraph in the early 2000s it was claimed that a BACS replica could be “converted to fire live rounds within about ten minutes using an ordinary household drill.” The Brocock ME38, a replica of a modern Magnum style revolver, was singled out as a particular menace.

Brocock BACS ME38

Now, you don’t have to be an engineer to appreciate that shooting a firearm cartridge from a replica designed as an air gun is likely to be as hazardous to the shooter as to anyone else, but that didn’t deter UK newspapers from trumpeting that converted BACS weapons had been used to commit crimes and murders. While it was certainly true that police in the UK impounded several BACS replicas which had been converted to take live rounds, I have been unable to find a single confirmed instance where an armed crime or a  fatal shooting in the UK involved a converted BACS replica. The reporting was typified by an article attacking Brocock and their BACS replicas (in the Daily Telegraph again) which highlighted “the shooting to death of two teenage girls just a few miles from the firm’s warehouse in Birmingham.” The killing of two teenage girls is a horrible and a tragic thing, but readers who were willing to persevere with the turgid prose learned that these shootings involved a conventional handgun and a submachine gun and were nothing to do with either Brocock or BACS. However the conflation of the murders and the alleged dangers of BACS within the article meant that most readers probably assumed that converted replicas were responsible. Especially Telegraph readers who, in my experience, prefer simple, easy-to-grasp concepts and have to move their lips while reading.

Even the BBC became involved when the usually rational Newsnight programme included a feature on BACS in 2002 in which the Deputy Chief Constable of Greater Manchester Police said that: “There is evidence which would justify banning them.”  Whether these replicas were actually being used by criminals or not, the media attack on BACS became so frenzied that it was almost inevitable that the authorities would respond.

The Death of BACS

In 2003 the UK government introduced the Anti Social Behaviour Act. The act included several changes to the UK Firearms Act including prohibiting ownership of ground-to-air missiles, hand grenades, firearms capable of burst or fully automatic fire and… “self-contained gas cartridge weapons.” This meant that Brocock BACS replicas and replicas from other manufacturers which used this system were effectively made illegal in the UK. There was an allowance for existing owners to keep their replicas, but only if they applied for and were granted a Section 1 Firearms Certificate, a lengthy, complex and expensive process which included a caveat that the BACS replica could not be sold or transferred to any other person. The new act came into force in January 2004 and owners of BACS replicas in the UK were faced with a stark choice: They were given just three months to either hand over their replicas to the police without compensation or to obtain a Firearms Certificate which meant that the replica became effectively without monetary value as it could not be sold. Fewer than 6,000 BACS owners applied for FACs and the vast majority of the remainder of these replicas in the UK were surrendered to the police and destroyed.

Pietta Colt chambered for BACS rounds

If you want to see a BACS  replica in the UK today, the only place to go is the Imperial War Museum in London which has on display a Brocock Texan BACS revolver and a Fox air rifle which also uses the BACS system. Or find someone lucky enough to have owned a BACS replica before the new legislation was introduced and who had the persistence to obtain the required FAC.


OK, I know I have already said this already but I think it bears repeating. These are technically interesting and fairly powerful replica air guns but if you live in the UK, just don’t. As recently as 2014 a man in England came very close to receiving the mandatory minimum five year sentence after he purchased a dismantled Brocock BACS replica at a car boot sale. Not realising what he had bought, the man sent the replica to an air gunsmith for refurbishment. The gunsmith reported the matter to the police and things got very nasty, very quickly. In the event the man only escaped a prison sentence because it was discovered that a couple of vital parts of the replica were missing, meaning that it couldn’t actually be fired. It’s horrendous to consider that you might find yourself serving a long prison sentence for what might easily be a genuine mistake. In the case of a private sale, it’s quite possible that the seller may have purchased a Brocock replica legally before 2003 and may not even realise that the law has changed. The responsibility lies with the buyer and the only way to be certain to avoid breaking the law in the UK (or anywhere else) is to be very, very careful about what you buy privately and to check that any replica weapon you own complies with relevant laws.

A recent meeting of the UK Brocock BACS Owner’s Club.

Everything said about the legality of BACS replicas also applies to German LEP (Luft Energie Patrone) replicas – these use basically the same system. Japanese airsoft manufacturer Tanaka also experienced similar problems with 6mm replica revolvers which used its Cassiopeia system. This involved filling each shell casing with a tiny quantity of green gas which was used to fire the BB. Despite the fact that these mainly plastic replicas shot with all the power of a gnat’s fart, in 2008 Japanese police swooped on Tanaka HQ in Tokyo, arrested company president Yoshimoto Tanaka and impounded all Cassiopeia revolvers. The reason cited was the same given in the UK for the banning of the Brocock BACS weapons: That they could easily be converted to fire live rounds. It’s worth considering that a fair number of replicas using the Cassiopeia system were sold around the world before they were outlawed, and if you happen to have one of these and you live in (for example) the UK, you may want to think very, very carefully about whether UK law would class these replicas as using a self-contained gas cartridge system. I have never heard of a prosecution for owning one of these, but a strict interpretation of the law might lead to the same penalties for owning a Cassiopeia system airsoft replica as for a Brocock BACS.

Using a self-contained air cartridge system allows the production of replicas which have a high degree of functional realism. However, as we have seen, concerns in various parts of the world about whether these replicas can be easily converted to firearms means that for many of us, they simply aren’t an option. But the question remains: Would you want one anyway? I’m afraid the answer is probably yes. The Brocock BACS replicas were produced using engineering and finish which puts many of today’s replicas to shame. They were weighty, well balanced and a delight to handle and shoot. The need to hand charge each cartridge was an issue compared to the convenience of using gas or CO2 and the cartridges needed frequent lubrication, but the shooting experience was incomparably better. If you’re lucky enough to live somewhere that these replicas are still legal and if you can find an old BACS replica for sale, you’re in for a treat. The rest of us will just have to be content looking at the pictures, sighing and wondering what might have been.

“If the law supposes that,” said Mr. Bumble, squeezing his hat emphatically in both hands, “the law is a ass – a idiot”.

Oliver Twist, Charles Dickens

Related Pages

Replica Pistols in Canada in the Post 1998 Era – Part 1

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