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Posted on 11/07/2004 2:33:37 PM PST by vannrox
I should like to extend my acknowledgements to Anthony Neophytou, president of the MECHEM Business Group, division of DENEL in South Africa and a developer of the NTW-20 rifle, and to Terry Gander - Editor of the JANE's Infantry Weapons, UK, for the provided technical information and sharing their professional opinion on the design and application of said weapon.
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This anti-materiel rifle is interesting from the two points of view:
- its function and purpose;
- methods of dealing with recoil.
The rifle is built around two cartridges: the South African MG151 20x83.5 mm and the Russian API or API-T 14.5x114 mm. Optionally, and for the purpose of decreasing cost of training, the rifle can be made in caliber 12.7 mm.
The NTW20/14.5 rifle is an anti-materiel weapon that can have many applications, including the Explosive Ordnance Disposal (EOD), i.e. in addition to a purely kinetic effect, the 20-mm warhead is the smallest round that can deliver a useful payload. Its fragmenting HE capability makes absolute pinpoint accuracy less vital, since target effect is not limited to bullet diameter.
Tony Neophytou believes that it is only after one fired both commonly available 12.7's and 20-mm NTW extensively, without sophisticated target acquisition equipment on ill-defined ranges, that the 20-mm shows its superiority. The ability to spot the fall of shot enables one to compensate instantly with rapid follow-up shots to achieve hits if necessary.
Very little experience exists with 20-mm rifles by military users. The number of such rifles commonly recognized and known to the world at large is rather scarce: Croatian RT20, Hungarian APH RK20 and, finally, the South African NTW-20/14.5 guns complete this list. No wonder, the usual comments are that acceptable recoil and accuracy cannot be had in a weapon sufficiently light to be man-carried. The NTW-20 has been able to dispel this, most shooters firing the rifle for the first time are pleasantly surprised, first by manageable recoil forces and secondly and most importantly the ease with which targets can be engaged. There is absolutely no doubt as to whether the target has been struck or not!
In 20-mm format the rifle fires the 20x83.5 MG151 cartridge fired by the Vektor 20-mm GA1 cannon; the round is manufactured by Pretoria Metal Pressings (PMP). Ammunition natures fired by the NTW-20 include HEI, HEI-T, SAPHEI and Practice. Muzzle velocity is 720 m/sec and the operational range is given as up to 1,500 meters. In 14.5-mm form the cartridge fired is the Russian 14.5x114 in API and API-T form; muzzle velocity is 1,800 m/sec and a maximum effective range up to 2,300 meters.
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The NTW-20 has been designed for maximum ease of use and low maintenance. The bolt action with three-shot magazine provided the most efficient system for accurate single shot fire. The high cost, complexity and lack of accuracy of a semi-automatic action is not justified, since the time it takes to re-acquire and accurately aim on target is much longer than it takes to reload.
The question is also often asked, - what happened to the WW2 20-mm rifles? They were conceived primarily as anti-tank weapons but their armor-penetrating capabilities were soon far outstripped by the armor of newer tanks. These weapons weighed as much as 100 kg and could hardly have been considered as man portable. The most significant difference between these and the NTW-20 is the role it plays and the reduction in weight and cost. The NTW-20 gives a user a cannon capability in a rifle configuration.
NTW-20/14.5 is aimed primarily for use by quick reaction, peacekeeping, and SPECOPS. Accurate long-range fire is available for high value targets, with low collateral damage. The actual deployment and use of the system varies between different nations and depends on doctrine and philosophy, and most importantly imagination of a shooter.
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The system is supplied with two backpacks, each weighing approximately 15 kg loaded. One accommodates the weapon receiver section, while the other contains all of its ancillaries including the barrel and ammunition. These allow the system to be carried into relatively inaccessible areas so that it can be deployed from the least likely or expected areas.
Reduction of weight is made possible by the efficient recoil system, which is built into NTW-20. First of all, 65% of the total weapon weight resides in the barrel action. This is able to recoil in a lightweight cradle or chassis. This free recoil is reduced by three separate devices that work in concert with each other. And that's where this rifle is interesting from the point of its concept!
The first of these is the hydraulic double acting damper, which soaks up the initial high velocity recoil (see diagram "NTW Recoil Management System"). The damper is provided with an expansion valve and chamber, which absorbs expansion of the fluid during climatic extremes. The standard damper can cope with temperatures of - 10° to + 60° Celsius. Also available are the dampers that can operate under the temperatures of - 25° to + 35° Celsius.
The second recoil absorber consists of a double acting spring buffer located in the lower rear chassis.
As the recoil slows, the hydraulic damper begins to do less work, but the spring buffer, as it begins to be compressed, works more efficiently near the end of its stroke. The graphs of these two systems neatly overlap each other to flatten the recoil peak, and extend the time over which the whole force is experienced. This yields a shove rather than the sharp high velocity kick, which is produced by systems not equipped with recoil management system (RMS).
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The major factor with recoil is not the total amount of energy but the rate and the manner with which it is generated.
By table "Group Sizes for NTW-20" one can judge the accuracy of the rifle shown by firing standard ammunition.
| SPECIFICATIONS | |
|---|---|
| 20-mm version | |
| Cartridge: | 20x83.5 mm MG151. |
| Operation: | manual bolt action. |
| Feed: | 3-round box-type, detachable magazine. |
| Weight, empty, kg: | 26. |
| Overall length, mm: | 1,795 |
| Rifling: | 1 full turn in 560 mm. |
| Length of barrel, mm: | 1,000 |
| Muzzle velocity, m/sec: | 720 |
| Muzzle energy, J: | 28,500 |
| Effective range, m: | > 1,500 |
| 14.5-mm version | |
| Cartridge: | 14.5x114 mm Russian. |
| Operation: | manual bolt action. |
| Feed: | 3-round box-type, detachable magazine. |
| Weight, empty, kg: | 29. |
| Overall length, mm: | 2,015 |
| Rifling: | 1 full turn in 406 mm. |
| Length of barrel, mm: | 1,220 |
| Muzzle velocity, m/sec: | 1,080 |
| Muzzle energy, J: | 30,675 |
| Effective range, m: | > 2,300 |
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Developer & Manufacturer:
MECHEM, a division of DENEL (Pty) LTD.
329b Mundt Street, Waltloo, Pretoria.
P.O. Box 912454, Silverton 0127
Republic of South Africa
Tel: +27-12 803 7290
Fax: +27-12 803 7189
| table 1. Group Sizes | |||
|---|---|---|---|
| Range, m | in windage, mm | in elevation, mm | rounds |
| 150 | 79 | 70 | 5 |
| 250 | 145 | 45 | 5 |
| 550 | 220 | 225 | 5 |
| 700 | 200 | 250 | 5 |
| 800 | 250 | 250 | 5 |
| 1000 | 700 | 600 | 5 |
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I'm surprised Kerry didn't use one of these for his duck hunt exhibition.
(brady bunch mode on)
This is a weapon that will obviously become the choice of gang members across the country. It must be banned now!
(brady bunch mode off)
It'll have to wait. The "new" hasn't worn off my S&W 500 yet.
Must have one. Has our Governator banned it yet?
Let's import as many as we can before Dick Durban gets any ideas....
The competition - Barrett XM-109:
http://www.freerepublic.com/focus/f-chat/1225111/posts
Shades of the Lahti and Boys rifles. The more things change....
I want one of those and the new Barret XM109..
Needs a bigger scope on it though.
(My 13B bias is showing..)
I want one. Really. I'm single now... no-one to count the $$ per trigger pull. Good ammo for a .50 costs about $6.50/per. Wonder what 20mm costs. Anyone got dies?
/john
And I thought action was just a change in linear momentum.
I think is needs extensive field testing... in Fallujah.
Barrett Firearms has a 20mm upper for their rifle already. Buy American!!!
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In 1977, I paid $75 for my first car. In 2000, I paid $175 for a scope MOUNT. The scope cost much, much more, but not as much as I paid for my first house.
You can't have too many elevation clicks (1/4 MOA/click) on a scope.
/john
Yep,
The gangsta's can sit in the burbs and pick of the inner city guys.
/john
re: "Must have one. Has our Governator banned it yet?"
Since it over 50 cal, it is considered a destructive device and would require a Destructive Device license.
If kerry had one of those he could knock the underwear clean off a vietnamese.
Yep...Be nice to have one...But I sure as hell would not be happy to be the one to have to horse it around in the field...hehehe
Can't sling the sucker...Well maybe...But somebody else has gotta bring the ammo!!!
Humble...This thing would almost field dress bambi for you...hehehe
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