The Receiver – The M03 receiver chassis is imbedded in the stock al-la the Blaser R-93. Although it has a receiver ring and bridge, their purposes are merely to provide a cosmetic similarity to traditional rifle designs and offer place for telescope installation. The spine of the system is the stock-imbedded metal underpart.
A single telescope mounting socket is machined into the square bridged receiver ring and bridge respectively. The bridge type telescope base unit which fit into these sockets is fitted with a 3-lug rotor catch, operated by throw levers, at each end. The lugs are slotted into the sockets and the throw levers are then pushed forward. The movement rotates the catches into the locked position. It is a very fast and effective system which offers 100% return to zero. Its main drawback though is that the scope has to be removed every time you want to change the barrel.
Despite the exchangeable barrels fitting into the receiver, it is not the receiver which holds the barrel in place, but the chassis and it is actually held in place by two captive Torx head screws which thread through the stock and its forend based metal chassis into studs on the bottom of the barrel.
The M03 can accommodate cartridges from as short as the .223 Remington (54mm) to as long as the 91,44mm of the .375 H&H Magnum and anything in between.
On traditional right handed bolt actions the receiver has a connecting wall on the left side between the receiver ring and bridge, while the right side is open to facilitate loading and ejection. In the Mauser M-98 and the Winchester M-70 this wall also contains the raceway for the left locking lug. The M03 contains no such wall. It does not make the M03 flex-prone. Remember that the locking lugs of the M03 lock directly into recesses in the breech of the barrel so all stresses are contained in the barrel with no stresses transferred to the receiver.
The receiver chassis imbedded in the forend also contains a lip which fits into a recess in the underside of the barrel to serve as an additional recoil lug. Not only is the recoil lug system inverted from traditional designs, but the compression strains generated by cartridge thrust against the bolt face and breech lugs are absorbed by the barrel and not the receiver.
The Bolt Assembly – The locking lugs on the M03 bolt head lock directly into recesses in the rear of the barrel.
The M03 bolt shaft is unusual. It is just a tube with four flat outer sides. Its only purpose is to serve as body for the bolt head-, bolt handle-, bolt sleeve- and striker assemblies. The bolt head is removable such as on the Lee-Enfield and it sports recessed locking lugs a-la the Weatherby Mk.V; six of them in three banks of two each. Interchangeable bolt heads for four different case head sizes are currently available on the M03.
The main benefit of the three sets of locking lugs is that it reduces wobbling of the bolt face under the immense back thrust generated during the firing of a cartridge to which dual lug systems are so prone. Any reduction in bolt wobble under back thrust represents an equal improvement in potential accuracy. The second advantage is that bolt lift is reduced to about 55° as opposed to the 90° required on traditional dual opposed lug designs.
The bolt is removed by depressing the bolt stop on the left receiver wall down, simultaneously pulling the bolt from the receiver. Very traditional, but the bolt stop catch sits flat in the wall without any protrusions.
The typical modern German cocking/de-cocking system as found on Krieghoff and Blaser rifles and doubles, rather than the traditional safety catch system of traditional rifles, had been adopted for the Mauser M03.
On traditional rifles operating the bolt cocks the rifle and compresses the firing pin spring. Although the firing pin does not touch the primer of the chambered cartridge, the safety has to be applied to mechanically prevent the firing pin from slamming forward when the trigger is pulled. Many hunters have adopted the hazardous habit of not using the safety on traditional rifles, but to pull the trigger while closing the bolt – thereby relaxing the firing pin spring. They forget that the firing pin then rests against the primer and that even a slight jar can bounce the firing pin and discharge the rifle. Others only partially close the bolt. I have often seen the bolt slip shut and the oblivious hunter ducking and diving through brush with a cocked and loaded rifle and a muzzle waving in all directions.
The German cocking system as used on the M03 is safer than traditional safety catch systems, but takes getting used to. It not only relaxes the firing pin, but it also eliminates contact between the firing pin and the primer of a chambered cartridge.
The heart of the M03 cocking system are the cocking lever tail which swings horizontally between the safe (S) and fire (F) positions, as well as the de-cocking button situated just below it and which protrudes from the rear end of the bolt shaft. It is very conveniently positioned for both right- and lefthanders and another reason why the M03 is available in both configurations at no extra cost. In fact a family like mine can have both configurations on a single rifle by simply switching bolts and then only the stock has to be ‘neutralized’. To cock the rifle you simply thumb the lever towards the ‘R’ and the direction is determined by the right or left handed configuration of the bolt used. To de-cock you press the button below the cocking lever and allow the lever to flip to the ‘S’ position. There is a trick; upon first closing the bolt, it will not allow you cock it. You have to cycle the bolt once before it becomes functional.
The M03 is equipped with the typical modern cat-nail extractor recessed in the bolt face and a plunger style ejector. There is absolutely nothing wrong with this for plains game hunting and many modern designs, the M03 being one of them, feeds and ejects as reliably as the more traditional dangerous game designs; if not more so. These modern designs are more prone to double feeding and jamming as controlled feed designs, but that is operator induced rather than a rifle design problem as I explained in the book African Dangerous Game Cartridges. Fact is – the nervous dangerous game hunter is better off with a controlled feed system than with an uncontrolled feed system.
I have nothing against non-rotating extractors, but I do distrust plunger ejectors. Dirt and grime affects their reliability and they cause the cases to constantly scrape against chamber and breach area walls.
Trigger – Two trigger types are available on M03 rifle. The set trigger version available on special order, is activated by pushing the trigger lever forward, but comes with a caution; if the set is engaged too vigorously it can trigger a shot unintentionally.
The standard, or direct trigger version is the more common type and conveniently profiled and contoured. The triggers remain in the stock when the rifle is dismantled. Accessing the trigger for maintenance or adjustment is a real issue. You need to remove the recoil pad and the retaining rod in the butt as well as the chassis before the trigger can be accessed.
The Magazine – The M03 magazine is a removable sheet metal unit with a synthetic follower (platform) which retains the cartridges in a traditional staggered column format. Five standard head sized and four magnum calibre fit into a magazine, while three is the norm for .404 Jeffery based cartridges.
The magazine can be locked in place by means of an override feature for those who do not like detachable magazines. The magazines can be filled in or out of the rifle.
The magazine release button is situated in front of the magazine box and you depress it with your index finger to drop the magazine box in the palm of your hand. It is far superior to traditional latch designs.
The magazines are long enough to accept .375 H&H Mag length cartridges. For shorter cartridges a synthetic spacer is placed in the rear of the magazine to keep short cartridges in position.
Barrels – A variety of round and fluted barrels are available from as short as 470mm (18.5”) to 600mm (23.5”) in 25 chamberings. With exceptions barrel increments generally are 20mm (0.8”).
Sights – Iron sights, even on dangerous game rifles, are becoming increasingly less common, especially amongst my generation with gradually failing eyesight. The M03’s iron sights are functional without being impressive.
The sight ramps are very elegant. The front sight is a non-adjustable round brass bead, while the rear sight sports a round notch on a flat-topped pyramid style blade. The blade obscures the minimum target area due to its sloped sides and is quite functional. A bright, blaze orange 3-dot system is also available and most likely the better option as it is incapable of an off-centre reflection as round brass beads are prone to do with sunlight coming in at an angle. On the Africa models a wide V rear sights blade is standard.
Stock – The M03 is available in walnut and synthetic material in about 14 different stock styles and counting. This aspect of the M03 actually requires an article all on its own. Butts can be had in straight combed classic and the European hog’s back styles. The grips are offered in modern classic or the curved German style, while forend options are classic, schnabel (beak) and a very elegant fullstock. Both walnut and synthetic versions are also available with a beautifully and practical adjustable comb as on target rifles.
Conclusion – As modern switch barrel rifles come, the M03 should find favour with most hunters. It is a growing concept traditionalists must come to grips with – even if not prepared to acquire.
Naturally free floating switch barrel systems do not have the tight forend to metal fit we see on custom rifles. I still have to overcome that prejudice, but this is a factory rifle and it is a well-made and mated firearm so judged. It is convenient to use and with the ammunition used it was as accurate as any traditional fixed barrel rifle I have fired.
German rifles tend to have overly complicated triggers from an African perspective and the M03 is no exception.