• Andrew

Air Craft of a Different Calibre


Let me transport you back about 35 years or so ago whilst standing in an uncut hay field waiting for the rabbit, 25 yards away, to pop its head up. I was downwind and had crept up close enough to make the shot count. All I had to do was “squeak” the rabbit up and on hearing the strange noise he would sit up to see what was going on.

However, this required a standing shot and holding the heavy scoped air-rifle steady for the snap shot was becoming increasingly difficult for I had been moving stealthily forward for the last five minutes with the rifle in my shoulder to minimise movement – there were rabbits everywhere.

The “squeak” certainly worked and up he popped alert to the noise. I shifted aim but the wobbles had started. The cross hairs danced above, below, left and right of my aiming mark. I continued to hold aim hoping to steady but the wobbles got worse until I snatched the shot and the rabbit ran off into nearby cover. How many times had this happened? Too many! The problem was this. The grass was too long for a prone shot and a kneeling shot required simply too much movement which would likely alarm the quarry. There was no doubt about it; it had to be a standing shot and what was needed was a lightweight rifle!

The Air Craft “Light Bulb” Moment The idea came to me two weeks later whilst soaking in the bath. I knew that any suitable piston air rifle within 12ft/lbs would be heavy, mine was a BSA Airsporter/Stutzen with plenty of hit but too heavy to hold on aim whilst walking-up. I rejected the idea of a Sheriden or Sharp Innova pneumatic pump-up as making too much noise and movement between shots (remember that this was at a time when precharge weapons as we know them today, did not exist).

Whereas, I had recently read about the Saxby and Palmer No.4 Lee rifle Enfield conversions firing pneumatic/precharge cartridges otherwise known as TAC (Tandem Air Cartridge) cartridges.

...and I had also read about how Morris and Aiming Tubes conversion made it possible to sleeve an existing barrel and chamber to accept a cartridge of lesser calibre.

Furthermore, I also knew, from my boyhood, that a .303 blank could be fired in a .410 shotgun and so began an idea that would turn into a working innovation.

The Build I discussed the idea with a gun maker who, at the time, specialised in pneumatic air cartridge weapons and he was confident that a .410 using a Saxby and Palmer type “.303” air cartridge (which is dimensionally similar to a .303 case) would be feasible for such a project and therefore to let him know if I wanted to go ahead. The next stage was to consider the weapon to be needed to be lightweight, bolt less and a non-ejector. WHY, I hear you say?

  • Lightweight - to walk up and hold on aim for an extended time.

  • Boltless - for silent cocking, breech opening/extraction and minimised hand movements.

  • Non-ejector - to prevent the loss of the valuable air cartridge in long grass.

  • Reloadable - on the aim. I was on the hunt for a hammer .410 and not before long, I spotted a skeleton stock, Belgian made “poacher’s” folding .410 for sale at £35.00 in my local gun shop. It was a shabby single barrel hammer gun but nothing that could not be refurbished and although the bore was tatty this was of no serious consequence once a Morris tube was fitted; importantly, everything was there and the action was tight. It did not occur to me that such an enterprise would not work and that the expense would be for nothing - such was my excitement at the challenge.

The modification programme commenced with the manufacture of the Morris tube in hard brass complete with breech chamber. The Morris tube floated on “O” rings at two points inside the barrel and slid in from the breech end with the new breech chamber fitting snugly inside the .410 chamber.

The new barrel was a .25 calibre micro groove, tight twist that did not extend to the full length of the .410-barrel; this I was assured, was the result of the ideal barrel length in relation to the air cartridge energy, and an added benefit of which was a noticeable suppression of noise when fired. (I have noticed when firing a piston air rifle that a single shot can alarm a field of rabbits whilst this rifle does not).

Also required was the silver soldering of a scope ramp to the barrel in order to fit a very compact Beeman 4 x 21 scope to minimise weight and generally enhance balance.

Test firing exceeded all expectations. Using lightweight .25 calibre Rhino waisted pellets, the gun shot flat like a .177 and hit like cannon ball. Here are shown a selection of different .25 airgun pellets compared alongside a .22 long rifle cartridge.

The next stage was refurbishment, so everything was dismantled. All screw heads were deburred, reshaped and polished. The hammer and side lever chequering were filed up sharp and all remaining metal parts sent out for industrial polishing.

Whilst the metal parts were away the stock and fore-end were stripped in Nitromors and the bruises steamed out. Using professional chequering tools the chequerings were all recut and then masked up. Next sanding down by hand commenced using the finest of sandpapers and grit 1200 emery paper until the wood shone. A subtle wood stain (Colron) was carefully worked-in by cloth to avoid shading and the chequering was unmasked and treated at the same time using a toothbrush. Remasking the chequering, the wood required repolishing with emery paper as the stain had gently lifted the grain. With the wood shining, three coats of shellac were applied using a Badger bristle shaving brush. Between each coat the surfaces were allowed to thoroughly harden and were gently levelled off using OOOO wire wool. Finally, the stock and fore-end were finished off with domestic furniture polish to give a lustrous finish.

With the woodwork complete, the metal parts came back from the polisher gleaming, ready to be degreased and put into my Blackodising tank. I had decided to black some of the screws, the barrel, side lever and trigger guard leaving the frame, hammer and trigger polished bright for contrast which has worked out quite well. The degreasing process required all metal parts to be tank treated at 100C in a degreasing solution. The Blacking process is more complicated and requires a delicate balance of water volume, heat and quantity of blacking salts to achieve the correct process temperature with depth of blackness.

On removal from the blacking tank the blacking salts had to be removed from all metal parts by washing-off with boiling water as failure to do this would result in unsightly efflorescence over time. To prevent any risk of rust forming on the parts as the boiling water evaporated, WD40 was quickly sprayed on. Once the parts were cool to the touch they were rubbed over with a clean cloth to remove oil and excess blacking and by now the metal was fully finished and shining.

The inside of the barrel was repeatedly oiled and dried using a .410 cleaning kit until all excess blacking was removed and finally the inside was anointed with silicone lube and the Morris tube inserted.

Final assembly was done using gunsmiths screwdrivers of the correct size to ensure avoidance of new metal burrs and bruises.

It only remained to fit the scope and sling mounts and I would be ready for sighting in. As previously stated the ammunition was .25 and chosen for its knock down power. The air cartridges are ingenious self-contained pressure vessels pumped up to 12ft/lbs using a simple “Slim Jim” hand pump.

Each cartridge comprises of two key components; a) the pellet holder and b) the pressure vessel. With a pellet loaded into the holder this screws onto the front of the pressure vessel once it has been pumped up with air.

Preparation is a lengthy process so I prepare a dozen or so cartridges at a time and leave the pump behind when out shooting. I find that with only twelve shots to place I pick my target with care and shoot sparingly which minimises intrusive shooting and ensures effective vermin control.

But how did it shoot I hear you ask and were all the design objectives fulfilled? The gun shoots very well, I zeroed at 30 metres and never got less than a one-inch group shooting from standing although by today’s standards that would be too loose for a precharge rifle. However where this gun will always offer superior performance is in holding aim at the standing shot and in discreet and silent handling. This air rifle was found to comfortably reach out to 70 metres with reliable accuracy for inanimate target shooting and Yes, I think it has been worth all the trouble although current Home Office Precharged Weapons licensing laws have required the gun to be taken off my shotgun certificate and put onto my FAC with the further provision that it can never be sold on to a new owner but instead must be broken up should I no longer be able to keep it.

The End of a Beginning - RIP

Established in the 1980s by Saxby-Palmer the air cartridge system was at the peak of its popularity when, two decades ago, the UK government outlawed the entire range of air cartridge-powered airguns by way of the Anti-Social Behaviour Act, 2003.

The Brocock Air Cartridge System (BACS) was an ingenious, self-contained portable airgun propulsion system, which is now all but extinct in the UK as the Act required shooters to either hand in their kit (with no compensation) or put it on a license. Those who chose to do the latter were not permitted to subsequently transfer their guns to other license holders; in effect, they became dinosaur guns.

Up until 2002, BACS air pistols and rifles were readily available on the UK airgun market. The popularity of the range was such that, by 2002, estimates put the number of air cartridge guns in circulation around the 70,000 mark. This figure included air pistols similar to the one seen below as well as air rifles manufactured to chamber BACS air cartridges.

However, a small number of incidents relating to the alleged illegal conversion of (mainly) Brococks to allow them to discharge live ammunition sparked a Press frenzy with the BBC reporting that National Criminal Intelligence Service data showed converted Brococks accounted for 35 per cent of all guns recovered by the police. In the months that followed intense media hype, a number of cases involving the illegal conversion of air cartridge airguns resulted in the call to restrict their sales such that, by March 2003, the government had included ‘self-contained gas cartridge weapons’ (SCGCs) in a white paper outlining its proposals for tackling anti-social behaviour. As a result of the illegal activities of a few criminals, the resulting Anti-Social Behaviour Act received Royal Assent in November 2003.

The Anti-Social Behaviour Act introduced a number of changes to the Firearms Act, 1968 as Section 39 of the Anti-Social Behaviour Act added air cartridge airguns to section 5(1) of the Firearms Act, thus classifying them as ‘prohibited weapons’ alongside ground-to-air missiles, sub-machine guns, grenades, pump-action shotguns and burst-fire automatic weapons!

From 20 January 2004, it became an offence under the act for anyone to manufacture, sell, purchase, transfer or acquire a Self Contained Gas Cartridge gun, and it was illegal to be in possession of one after 30 April 2004 unless you had a Section 1 Firearm Certificate. Penalties for non-compliance were fixed at a mandatory minimum imprisonment sentence of five years, up to a maximum of 10 years leaving airgunners with air cartridge guns with two simple choices: surrender their kit to the police without a penny of compensation; or apply for an FAC.

Interestingly, the Home Office subsequently reported that fewer than 6,000 BACS airguns had been entered on firearm certificates in the UK, which makes legally-owned air cartridge models some of the rarest modern-day airguns in circulation today. Ironically, though, because they can’t be transferred between owners, these guns have no material value whatsoever – although their owners will tell you that they consider their Brococks ‘priceless’!

While it is fairly clear to see why these airguns were so attractive to the criminal fraternity, it’s also as easy to see why they were so popular with the law-abiding airgun community.

The operation of the BACS system was, and still is for a minority of airgunners lucky enough to have them on ticket, the closest thing to handling real firearms but without all the power and noise. The BACS cartridge, just like a live round, is entirely self-contained. It holds the projectile – the pellet – and the source of propulsion needed to fire it: compressed air. No other airgun operates this way.

The cartridge really was a work of genius. Its body was brass, which incorporated a sophisticated valve and seal system, onto which screwed a nose cone to hold the pellet. The body was effectively a mini air chamber, which was filled with compressed air in one of three ways: via a hand-operated “Slim Jim” pump, a stirrup pump or a ram-charger which attaches to a diver’s tank.

The Slim Jim hand-pump was by far the most economical in terms of cost, but most expensive in terms of effort as, typically, each cartridge required eight strokes of the pump. Charging just 12 cartridges required time and patience!

Because of their added ‘realism’, the original range of Brocock BACS airguns, although small in number, was diverse enough to appeal to a great many airgunners in increasing numbers and the range eventually developed to include rifles and pistols available in both .177 and .22 calibres.

Today there are a very small number of BACS in legal ownership and active use and for sure, numbers in use will dwindle as spare parts for maintenance becomes scarcer and FACs expire and aren’t renewed.

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