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Voici un article de Kit-up! sur les essais d'une minimi modifiée pour tirer du 5,56 télescopé:

Army Closer to Era of Lightweight Ammo

In an exclusive story to be posted on Military.com tomorrow morning, Kit Up! has learned that the Army is in the final stages of planning a major field test of a weapon designed to fire ammunition that weighs half of what current rounds do.

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The so-called Lightweight Small Arms Technologies program run out of Picatinny Arsenal, N.J., has come a long way in the development of cased telescope ammunition that uses a plastic shroud to contain the propellant and 5.56 bullet instead of brass.

Readers will recognize this technology has been around since at least the late ’70s, but only now have real resources been brought to bear on the idea. The program, run out of the Joint Service Small Arms Program office, will field at least eight SAW-like machine guns to troops for an exercise in the summer of 2011 to see how the reduced weight and reliability helps the mission.

The experimental SAW with 600 rounds of cased telescope ammo weighs 23.8 lbs — the current one comes in at 38.3 lbs with ammo.

We’ll talk more about this tomorrow on Kit Up!, including a belt-fed battle rifle the engineers are thinking about putting together that weighs as much as an M4. But be sure to read tomorrow morning’s Military.com for the full story.

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Deuxième partie:

A SAW at half the weight? It's for real.

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From this morning’s Military.com lead story (I’ll run through it with some commentary):

Army Engineers at the Picatinny Arsenal, N.J.-based Joint Service Small Arms Program office have been working for the last six years on a radical approach to ammunition and weapons that has the potential to cut the weight Soldiers carry by nearly 50 percent.

Researchers are using so-called “cased telescoped” ammunition that does away with the propellant-holding brass shell and replaces it with a lightweight plastic case. So far the program, dubbed Lightweight Small Arms Technologies, has built three M-249 Squad Automatic Weapon-like machine guns and fired more than 10,000 of the lighter rounds with the same rate of fire and accuracy of a standard SAW.

A couple quick things here…According to Kori Phillips, lead engineer on the program, the JSSAP office was told by the infantry center at Benning to concentrate on the light machine gun — in this case the SAW. So at least to some extent, the Army has telegraphed its priority as lightening the M-249 in one way or another (they recently did it with the M-240 by fielding the Mk-48).

And one other interesting thing of note is that they developed a whole new firing system for the LSAT SAW that has a rotating bolt…

The new cased telescope-firing SAW looks almost the same on the outside as its M-249 counterpart but uses a rotating action and a novel feed system that fires a standard 5.56mm ball projectile and ejects the plastic case and link from its own port.

“One of the other things we’ve completely avoided in this system is the failure to feed and failure to eject,” Phillips added. “In your SAW system, that’s where you primarily have failures and malfunctions.”

According the Phillips (and I only half understand what she’s even saying) the chamber supports the entire length of the case which is “key with a polymer case. You can’t have any exposed surface otherwise it will sheer.” It’s a straight through feed and eject and the chamber is not attached to the barrel. Also since the weapon is lighter, it has a lot more kick than a SAW. So engineers put in a “long stroke soft recoil” spring system in it, “so there’s no buffer spring in the butt stock.”

Engineers have also built a prototype M-4 that fires the lighter rounds. The experimental M-4 weighs about the same as a standard M-4 but has a 40-round magazine that’s slimmer than the current one and straight instead of curved. And since half the weight of a legacy bullet is due to the brass case, a Soldier’s load of more than 200 rounds in combat will drop substantially.

Phillips admitted you can’t shave much weight from the already pretty light M-4 system. But the unique characteristics of the ammo allow engineers to fashion a straight mag, just as long as the current one but with ten more rounds.

The M-4 variant of the cased telescope rifle has a so-called “rising chamber” action that’s fed ammo from the rear — what JSSAP engineers jokingly call a “fauxpup” after the so-called “bullpup” operating systems popular with European small arms. It looks similar to a standard M-4, but the operating system actually gives the experimental rifle an extra four inches of barrel length, Phillips said.

The rifle looks almost the same as the M-4 — no magazine behing the trigger, Stoner lovers — but since the ammo is fed from behind the bolt, the same size gets four extra inches of reach out and touch you.

While the cased telescoped ammo is almost ready for prime time, the more exotic caseless rounds still need some work, Phillips explained. Testers are having problems keeping the rounds — which are essentially hard, molded propellant with an embedded 5.56 mm bullet — from degrading in high heat. They’re also expensive, hard to make, and tough on the shooter.

Now here’s where things got dicey. The caseless ammo is just simply not there. Though it offers a huge advantage in weight and volume, the instability of the round and its expense and difficulty in manufacturing have kept it in the lab. But I’ve been around more than a few SAW gunners who’d take the 40 percent weight reduction over nothing any day.

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Chez Military.com, il y a ceci:

New Ammo Slashes Machine Gun Weight

July 23, 2010  Military.com  |  Christian Lowe

Army Engineers at the Picatinny Arsenal, N.J.-based Joint Service Small Arms Program office have been working for the last six years on a radical approach to ammunition and weapons that has the potential to cut the weight Soldiers carry by nearly 50 percent.

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Researchers are using so-called "cased telescoped" ammunition that does away with the propellant-holding brass shell and replaces it with a lightweight plastic case. So far the program, dubbed Lightweight Small Arms Technologies, has built three M-249 Squad Automatic Weapon-like machine guns and fired more than 10,000 of the lighter rounds with the same rate of fire and accuracy of a standard SAW.

"This delivers the same lethality as the systems you already have, but it's a lot more effective because it's much lighter," said Korene Phillips, lead engineer for the LSAT program, in an exclusive interview with Military.com.

Engineers have also built a prototype M-4 that fires the lighter rounds. The experimental M-4 weighs about the same as a standard M-4 but has a 40-round magazine that's slimmer than the current one and straight instead of curved. And since half the weight of a legacy bullet is due to the brass case, a Soldier's load of more than 200 rounds in combat will drop substantially, Phillips said.

Born of the Army's "Advanced Combat Rifle" search in the 1980s, cased telescoped ammo and the much more technically complicated "caseless" ammunition were relegated to the laboratory after the Army shifted its gaze toward greater lethality rather than weight reduction, Phillips said. But with the U.S. military involved in two combat zones and a renewed emphasis on shaving pounds off a trooper's load, the Army decided to take another look at the decades-old technology.

"What we were trying to do back then was decrease load and increase lethality," Phillips said. "And we liked to joke that that was breaking the laws of physics."

With millions of dollars in Army research investment, the JSSAP office says it will be ready to put weapons in warfighters' hands by next year. Phillips said eight new SAWs will be built by AAI Corporation. She also said that the office plans to run an exercise with an infantry squad equipped with the new lightweight machine gun and 100,000 rounds of cased telescoped ammo.

It's unclear what unit will get the experimental weapons for the test, which is slated for the summer of 2011, but the Army, Marine Corps and Special Operations Command are playing a key role in LSAT development, Phillips said.

"We're just trying to get a comparison of the squad as it is today with the M-249" and the experimental weapon, Phillips said. "Our plan is just to replace the M-249 in the squad with the [new] weapon and see where that gets you with improvements in your time to complete the mission and your ability to complete the mission."

The standard SAW gunner's load comes in at around 40 pounds, Army officials say, which includes the weapon itself and 600 rounds of ammo. The experimental machine gun with cased telescoped ammo load comes in at 24 pounds.

The new cased telescope-firing SAW looks almost the same on the outside as its M-249 counterpart but uses a rotating action and a novel feed system that fires a standard 5.56mm ball projectile and ejects the plastic case and link from its own port.

"One of the other things we've completely avoided in this system is the failure to feed and failure to eject," Phillips added. "In your SAW system, that's where you primarily have failures and malfunctions."

The M-4 variant of the cased telescope rifle has a so-called "rising chamber" action that's fed ammo from the rear -- what JSSAP engineers jokingly call a "fauxpup" after the so-called "bullpup" operating systems popular with European small arms. It looks similar to a standard M-4, but the operating system actually gives the experimental rifle an extra four inches of barrel length, Phillips said.

While the cased telescoped ammo is almost ready for prime time, the more exotic caseless rounds still need some work, Phillips explained. Testers are having problems keeping the rounds -- which are essentially hard, molded propellant with an embedded 5.56 mm bullet -- from degrading in high heat. They're also expensive, hard to make, and tough on the shooter.

"We haven't had any volunteers to shoulder fire it," Phillips joked, adding her office hasn't gotten the approval to take it to the range. Excessive smoke, inexact timing and other uncertainties have kept the weapon attached to a bench.

"Nobody's knocking on my door asking to shoot it," she added.

Despite the immaturity -- and danger -- of the caseless technology, the Marine Corps is spearheading the research into the ammo because of its advantages in weight and size.

"It's a significantly smaller round of ammunition," Phillips said. "So from a Marine perspective, that's a big deal because of the way they travel."

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  • 2 weeks later...

je crois que j'ai un PDF qui parle de cette munition, je le chercherai et avec un peu de chance je le mettrai en ligne. Ca avait l'air assez prometteur, mais le prix de la cartouche grimpera sans aucun doute.

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  • 11 months later...

Un petit article de Kit-Up! Sur les tests des munitions télescopées:

Revolutionary Ammo Set for Troop Test

Published on July 6th, 2011

Written by: christian

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The Army is set to test a radically-designed new machine gun that fires space-aged ammo that’s half the weight of today’s cartridges.

The so-called “cased telescoped” ammunition program, which is part of the Army’s Lightweight Small Arms Technologies program, has shown promise over the past couple years and earned some funding for an initial usability test with Joes at the Maneuver Battle Lab at Benning.

The engineers at Picatinny are sending eight M249 SAW-like prototype machine guns that are specially-designed to fire the cased telescoped ammo for testers to put through the paces, including shoot house runs, field maneuvers and range quals at the squad and individual level. They’ll have 50,000 rounds on hand for the tests.

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“They’re setting up some testing that’s going to show us if we’re on the right track, and if the weapon system does what it’s supposed to do and also if the reduced weight of the system is beneficial to the individual and the squad,” said lead engineer Kori Phillips, in an exclusive interview with Kit Up! on June 30.

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As we noted back in our post last year, the cased telescoped ammo uses a plastic case rather than a brass one to hold the propellant — kind of like a conventional shotgun shell. It has a rotating action that ejects the link and plastic case from its own port, a design engineers say completely eliminates the failure to feed/failure to eject problem with rapid firing a conventional SAW.

Phillips said the tests at Benning will begin in September and last about three weeks. Then the program is in limbo since it received no money for fiscal 2012. Phillips hopes that if the tests go well, it will get the notice of Army weapons developers and get some cash funneled its way for more weapons and a bigger trial.

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“We don’t really know what’s going to happen with this program,” Phillips said. “If we want to do something additional, we basically have to pass the coffee can.”

Testers also just finished evaluating the critical action of an M4 variant that fires cased telescoped ammo (it’s not a full weapon, just the parts that fire rounds), and Phillips said the program is funded to build a prototype for field trials next fiscal year. Phillips also said her engineers have veered away from a Bullpup design for the M4 variant, explaining that it was “causing them some complications that made it not worth doing.”

Engineers with LSAT are also putting the idea of caseless ammo (which derives its rigidity from a hardened propellant) on the back burner (no pun intended) since the chemistry of the propellant that’s safe enough for Joes to use is so-far too expensive to make in bulk.

“It’s very slow going,” Phillips said, “that’s the only way to describe it.”

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Pour ceux que le sujet intéresse, je conseille d'aller faire un tour du côté des présentation du symposium annuel sur les armes légères organisé par le NDIA.

Les dernières infos sur le projet LSAT, c'est sur http://www.dtic.mil/ndia/2011smallarms/Tuesday12170Phillips.pdf

Même si le projet a l'air intéressant, je précise tout de même qu'on peut arriver au même résultat niveau poids en utilisant les dernières générations de mitralleuses comme le FN HAMR (http://www.dtic.mil/ndia/2011smallarms/WednesdayWeapons12299Gavage.pdf) et des 5.56 avec étui en polymère( http://www.dtic.mil/ndia/2009infantrysmallarms/tuesdaysessioniii8550.pdf).

Je suis donc d'avis que le LSAT n'a absolument aucun avenir vu les changements logistiques nécessaires pour un gain marginal par rapport à des systèmes (rétro-)compatibles avec les standards actuels.

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ce n'est pas le première tentative US de développer des munitions télescopées. La firme AAI a travaillé sur le sujet il y a bien des années pour une mitrailleuse destinée à remplacer la minimi. Et on se rappelle que les chars légers de la RDF étaient armées de 75 CTA et que le programme ACF de l'USAF (qui débouchera sur le F22) prévoyait un 25 mm CTA pour remplacer l'inoxydable Vulcan de 20 mm;

la techno CTA réduit le volume fonctionnel des munitions, ce qui entraine mécaniquement une réduction du volume, donc de la masse des armes.

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Un truc m'échappe : en quoi le fait de téléscoper les munitions permet de les rendre moins volumineuses ? Il ne faut pas le même volume de poudre derrière le projectile pour avoir la même puissance ?

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Vraiment interressant cette histoire de munition télescopée

Mais il me vient plusieur question

Les MT (munitons télescopée) ont un poid réduit par rapport au MC (munition classique) et sont aussi moins long, mais est ce que l'épaisseur de la cartouche change ?

Une mouvelle cartouche necéssite telle un nouveau fusil ou alor une legère trasformation sur la arme moderne (HK 416, SCAR, etc) ?

Dans combien de temp pourrons voir ca en france ?

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Les MT (munitons télescopée) ont un poid réduit par rapport au MC (munition classique) et sont aussi moins long, mais est ce que l'épaisseur de la cartouche change ?

Le diamètre change en effet.

Pour les blindés, ce n'est pas un problème. Ce qui compte, c'est la longueur totale de la munition.

Une mouvelle cartouche necéssite telle un nouveau fusil ou alor une legère trasformation sur la arme moderne (HK 416, SCAR, etc) ?

Comme on le voit bien dans l'article canadien, le mécanisme emploie des culasses rotatives. Donc le mécanisme change complètement. On ne peut plus employer les anciens systèmes moteur.

Dans combien de temp pourrons voir ca en france ?

50 à 70ans peut être.
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Comme on le voit bien dans l'article canadien, le mécanisme emploie des culasses rotatives. Donc le mécanisme change complètement. On ne peut plus employer les anciens systèmes moteur.

Est-ce que quelqu'un sait comment fonctionne le mécanisme des SAW montrées plus haut ? J'ai du mal à voir comment marche une action rotative avec une alimentation par bande (pas trouvé de schéma pour ces SAW)
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en quoi le fait de téléscoper les munitions permet de les rendre moins volumineuses ? Il ne faut pas le même volume de poudre derrière le projectile pour avoir la même puissance ?

Si mais un cylindre est plus "compact", donc le volume nécessaire pour stocker x munitions est réduit, de l'ordre de 12%.

Les MT (munitons télescopée) ont un poid réduit par rapport au MC (munition classique)

Non, les munitions avec étui polymère ont un poids réduit. Rien n'empêche de faire des munitions téléscopées avec étui en bronze tout comme rien n'empêche de faire du 5.56 classique avec étui polymère (j'ai posté un lien vers une telle munition qui est à l'étude).

Dans combien de temp pourrons voir ca en france ?

Probablement jamais vu qu'on peut obtenir 90% du résultat (niveau poids) en continuant à utiliser les armes et la chaîne logistique actuelle mais en passant à des munitions polymères.

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  • 3 years later...

article interessant sur DSI 107 sur les nouvelles armes d'appui de l'infanterie américaine avec reprise des programmes de munition casetelescoped et caseless . A priori la seconde technique serait plus performante mais pas tout à fait au point . Ce qui me sidère concernant ces programmes qui ne concernent après tout que des armes légères leurs munitions , c'est que l'US Army investi depuis dix ans , sans résultats probants autre que quelques séances de tir . Sachant pourtant que l'enjeu est primordial avec des gains de poids de l'ordre de 40% tant pour les munitions que pour la mitrailleuse légère , pourquoi ces technologies ne sont-elles pas généralisées ; que l'on mette 20 ans au moins à concevoir un nouvel avion de combat , soit , mais une munition de petit calibre ! on en a conçu d'excellentes au xixème siècle qui sont toujours en service ( 9 mm , 7,62x54 russe , 22lr ..) alors je m'interroge , y a t'il un vice caché ( l'article est plutôt élogieux ) , on parle de culasse basculante , est-ce que cela complique singulèrement la mécanique ? Imaginons qu'à poids égal , on pourrait  adopter un FA 7,62x51 avec presque autant de munitions qu'un 5,56 ! ça vaut quand même le coup , ou équiper chaque troufion avec la puissance de feu d'une mitrailleuse légère ! Autant les programmes type oicw étaient d'emblée condamnés , autant un progrès de 40% sur le poids c'est un bond en avant formidable . Après ce que l'article ne dit pas c'est si ces munitions necessitent absolument de nouvelles armes pour être tirées , avec cette fameuse culasse basculante . Si certains ont de plus amples connaissances sur le sujet , merci d'avance .

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article interessant sur DSI 107 sur les nouvelles armes d'appui de l'infanterie américaine avec reprise des programmes de munition casetelescoped et caseless . A priori la seconde technique serait plus performante mais pas tout à fait au point . Ce qui me sidère concernant ces programmes qui ne concernent après tout que des armes légères leurs munitions , c'est que l'US Army investi depuis dix ans , sans résultats probants autre que quelques séances de tir

On a pourtant énuméré de nombreuse fois ici la complexité qu'il y a a enlever l'étui ... étanchéité tenu de la munition contre les élément etc. etc. en gros on sait faire mais ca marche beaucoup moins bien.

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Oui mais ces des problèmes ont été identifiés depuis le G11 dont le développement a commencé en 1968.

ça fait quand même un vingtaine d'année de travail sur ces éléments (68 à 90) plus encore une dizaine d'année depuis le début du LSAT (2004) et ça commence à peine à arriver à maturité.

Maintenant, on peut voir ce programme comme une n-ième victime de la fin de la fin de la Guerre Froide. Après tout, HK avait grosso modo trouvait les solutions aux problèmes évoqués et le G11 fonctionnait. S'il avait été adopté, le concept aurait été amélioré progressivement aux cours des années 90 jusqu'à ce qu'il soit 100% mature aujourd'hui.

Si en 10 ans, les US ont pas pu faire de ces technologies la norme, ça a probablement plus à voir avec un manque de volonté de le faire que de véritables problèmes techniques. Les alternatives existent (les ALI  que l'on utilise aujourd'hui) et fonctionnent suffisamment bien par rapport aux gains du LSAT. Et étant un programme pas aussi visible qu'un programme d'avion de combat, VCI ou hélico, le nombre d'entités ayant un intérêt à le voir aboutir est largement plus faible.

 

Par contre, certaines briques du programme G11 sont devenus la norme entre temps. Le recours aux optiques, les canons flottants, etc. mais pas les munitions.

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Après tout, HK avait grosso modo trouvait les solutions aux problèmes évoqués et le G11 fonctionnait.

Pour le caseless, le probleme de la durabilité de la munition exposée aux intemperries a été réglé?!

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Pour le caseless, le probleme de la durabilité de la munition exposée aux intemperries a été réglé?!

La cartouche a une "graisse" protectrice, donc la munition reste viable à moyen terme. Mais le vrais problème des caseless c'est qu'elles se cassent régulièrement durant le chargement de la cartouche dans la chambre... Et ça je crois pas que ce soit résolu si ?

Edited by Conan le Barbare
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Pour le caseless, le probleme de la durabilité de la munition exposée aux intemperries a été réglé?!

En tout cas, en 1990, l'armée Allemande semblait prêt à passer commande et HK prêt à commencer la production plein pot. 

Est-ce que les cartouches auraient tenu le choc lors de manœuvres grandeurs natures, je ne sais pas. Mais si non, il aurait bien fallu qu'ils règlent le problème.

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