The TMP

Select Fire Steyr: The TMP

By Jacques Lenaerts

 
Three years ago, during a visit to the Austrian Steyr-Mannlicher company, I had a short look at a compact 9mm submachine gun, called the TMP, that I was allowed to handle very briefly. I remember wondering why Steyr was trying to develop a new 9mm SMG: there are already plenty of these weapons and the market for them is quite restricted. Further contacts with a company's representative changed my mind: each time, we briefly discussed the progress of the TMP. I came to suspect Steyr of working towards something else than a classic SMG, clearly developed to compete with the Mini-Uzi or the Heckler & Koch's MP5K family and the like.

I was right. As a matter of fact, this short-sized SMG came out of the same military concems that repeatedly led the U.S. Infantry School to start a new approach to the Personal Defense Weapon (PDW), now set within the frame of the Objective Family of Small Arms (OFSA). These concerns are shared by most modern armies and arose from the poor efficiency of the semi-auto pistol when used under true combat conditions as a last ditch defense weapon, especially by those people whose primary task is not to fight.

Steyr's designers were fully aware of this problem ever since the AUG assault rifle was put on the drawing board in the early seventies. Keeping in mind the main functions of the possible users, they fixed their eyes on a lightweight and compact PDW system which also had to provide firepower and to be easily controllable by a non-expert shooter. This system had to give the same firepower as a submachine gun, while having a pistol-type weight and length.

True controllability in firing bursts was a stringent requirement. In addition, the designers started from nothing except the company's know-how with composite materials. These materials were expected to help achieve controllability and keep the cost of the weapon within the same range as those of military pistols. It was clear that the system had to fire a pistol ammunition. Various calibers were taken into consideration and tested. Not surprisingly, the wide-spread 9mm Luger was regarded as offering the best compromise. Last but not least, the effective range was set at 25m, a distance you can see as really getting modest. These requirements sounded somewhat contradictory and I wondered how Steyr would manage to handle the whole package, as controllability still seemed to me hardly compatible with the other characteristics. But as stated by the manufacturer, this key factor was achieved through design, operating principle and rate of fire.

The TMP is quite evidently a light and compact weapon, with a length of 280mm and an empty weight of 1.3 kg. But at first glance, I was also struck by its rounded shape and smooth surfaces, which prevent snagging. This is another obvious benefit of the dark grey, high-impact resistant composite materials used to mold, in a very ergonomic fashion, as many parts as possible - mainly the 20- and 30-round magazines, cocking lever, upper and lower receivers, the latter being integral with grips, trigger guard and front guard.

The Austrian weapon differs from conventional machine pistols in its very tight structure. The moving parts are enclosed in the upper receiver, of which the ejection port is sealed by the breech assembly in its forward position, thus protecting the mechanism against external dirt and water. The trigger group, the hammer unit and the safety devices are seated in the lower receiver, which is held together with the upper receiver by a sliding lock very similar to the one appearing on the Glock pistols and located above the front grip; it allows a fast field stripping in seconds.

Fixed to the upper receiver, and from the front to the rear, the forward end of the barrel is fitted in a protruding sleeve, whilst its rear portion is partly surrounded by a telescopic-style breech, the top of which holds a conventional recoil spring and its guide.

As described by the builder, the action consists of a delayed blowback, closed-bolt system with a rotating barrel. But I would say that the general operating principle is the same as on many short-recoil operated semi-auto pistols. At the moment of firing, the barrel is internally locked to the breech. Initially, it moves back with the breech under gas pressure, but after a 4mm run, it starts rotating clockwise. This is controlled by a cam fixed to the forward sleeve, which engages a slot on the side of the barrel. By the time the cam reaches the end of the slot, the barrel has stopped moving, but will have rotated enough for the breech to have unlocked itself. The breech continues moving to the rear, extracting and ejecting the empty case. This action is strictly reversed in the forward movement of the working parts; the breech is thus positively locked upon firing, whilst also delaying the subsequent opening. This helps to limit the recoil impulse, and to reduce the cyclic rate, which is 800-900 rounds/min.

The weapon controls fit very well into the overall shape of the TMP, being well-proportioned and easily accessible. Just have a look at the cocking lever, located at the rear of the upper receiver, or at the bolt-catch lever, the magazine catch and the sights, which, integrated to the top rib of the casing, have a very low profile. The trigger is of the selective type as with the AUG ; by increasing the pressure, you go from semi-auto to full auto fire - at least if the horizontal, sliding button-type safety catch is pushed half way across. If fully across, it allows automatic fire only.

Apart from the usual safety mechanism which prevents firing when the breech is not fully closed, the TMP features a drop safety preventing accidental discharges, whether the manual safety has been applied or not. Furthermore, the hammer is locked until the trigger is fully moved to the rear.

No shoulder stock is provided; Steyr's belief is that a stock will increase engagement times where the soldier is facing successive targets. The TMP must be easily handled under stress and be instantly ready to fire. This is assisted not only by the forward grip, but also by the sling; the weapon being carried at the side of the body, the user only has to grasp it with both hands and to aim at arm's length. If properly adjusted, the sling will tighten and bring the weapon into a perfect firing position. Apart from a silencer, the TMP is also designed to accept optical sights; these would fit onto a slide which is moulded into the upper receiver, as an integral part of it. Cigarette-sized laser sights of the latest generation could also be easily integrated.

When I arrived at Steyr's shooting range, I felt quite skeptical about the effectiveness of the TMP at the given range. I knew from previous experiences that short-sized SMGs are rather difficult to control, especially if you do not practice every day or every week, which is the case for most intended users. In any case the weapon impressed me favorably, as the two grips immediately offer a perfect hold due to careful design, spacing and slope. When you hold the TMP at arm's length with the forward hand pushing the front grip and the trigger-hand pulling the pistol grip as if to "stretch" the weapon, the gun is automatically brought into a central position, at face level (please notice this was done without a sling). It doesn't matter whether you are left- or right-handed; you not only get a very instinctive firing position, but you also spontaneously use both eyes when aiming. As I had been advised to fire in sustained bursts from the start (this had also to prove the mechanism), I had magazines filled with 15 and 20 rounds. I had nothing to do but empty each magazine in a single burst at a 10m target. That's what I did.

It is difficult to tell how deeply astonished I was at seeing the TMP remain almost perfectly on line, without climbing and without having to pay special attention to the grip on the weapon. Even before seeing the target, I had a new idea of what stability means. This was confirmed by the results of the successive full-length bursts; the early one was concentrated in a 25cm group, but the size of the groups decreased as the TMP became more familiar to me. It may reasonably be assumed therefore that 15cm groups at that range would be possible with little practice. Of course, there is a little spread, but this is mostly due to the shaking of the weapon when firing successive shots at high rate. Indeed, at a 25m range, the spread could help to improve the probability of hit, since it might compensate for slight aiming errors which are fairly usual in close-combat situations.

Shorter bursts of two to four rounds were controlled in the same way but, as I carried out the test firing in a narrow tunnel range, I was unable to engage targets using short bursts at longer range. However, considering the results, I am inclined to support the claims of the manufacturer.

Not only is the TMP remarkably compact and easy to handle but, of all the small SMGs I ever have had in my hands, I would say that it is by far the one that best combines the three basic features a military user has a right to expect from an automatic personal defense weapon: instinctive aiming, probability of hit and controllability.

 

Originally published in the July 1993 edition of Guns Magazine