Army Awards Contract for 7.62mm LSAT by Matthew Cox on June 6, 2014 · COMMENTS (23) Small-arms innovation programs may not be a high priority these days, but the U.S. Army continues to invest in its dream of a family of ultra-light infantry weapons. The service awarded a $5.7 million contract last month to Textron Systems to develop a 7.62mm version of the Light Weight Small Arms Technology MG as well as a carbine variant. The Army has had a strong interest in LSAT for the last decade. The system is far lighter than traditional machine guns, mainly because of its use of cased-telescoped ammunition. LSAT’s cased-telescoped 5.56mm ammunition relies on a plastic case rather than a brass one to hold the propellant and the projectile, like a conventional shotgun shell. It weighs about 37 percent less than standard belted 5.56mm. The 5.56mm LSAT weapon itself weighs about half as much as the 17-pound M249 squad automatic weapon. “The LSAT Light Machine Gun recently took part in the Army’s Dismounted Non-Networked Experiment at Fort Benning, Ga., receiving positive user feedback,” according to a press release from Textron Systems. Under this two-year award, the LSAT team will develop a cased-telescoped carbine, as well as 7.62mm CT ammunition and a machine gun operating mechanism, the release states. The team includes Alliant Techsystems, ARES Incorporated, MSC Software and St. Marks Powder. It plans to build on the current LSAT technology, which consists of includes the compact light machine gun with a quick-change, 12-inch barrel and folding buttstock. It was developed for close-quarters applications and tested in 2012 by the U.S. Army Special Operations Command. The effort has also produced the operating mechanism for a carbine variant. Read more: Army Awards Contract for 7.62mm LSAT | Kit Up! Kit Up!
Do they issue a knife to scrape out the melted plastic case when it jams? The brass case helps transfer some heat with firing in full auto mode. (shrug) I doubt we'll see this kind of ammo deployed in out lifetime.
Polymers can easily be engineered to have higher melting temps than 'plastics'. Not sure about the specifics on the casing in question but certain polymers have more of a glass like crystalline structure and hardness and tend to decompose at higher temp rather than melt. Polymerization was one of the more interesting subjects covered back in Organic Chemistry! Watching a few other videos about the LSAT shows that they are developing a completely 'caseless' ammo where all materials but the projectile itself are expended at firing. Seems this tech has been around for a great many years but has not really been utilized to any degree so far. Caseless has its pluses & minuses. No picking up piles and piles of brass and then storing, cleaning and sizing it. Very nice feature! But impossible to roll one's own... At least until the materials and equipment are made available & affordable. I personally can't wait for the day caseless is the standard. Definitely some obstacles to overcome before that day arrives though. Currently, AK-47/74 steel cased rounds are polymer coated. They are the greyish looking cases as apposed to the lacquered OD green cases. The polymer coating undergoes a liquification process that seals the chamber at time of firing. It does not melt. I have fired a gajillion (technical term for a lot!) through my 7.62 AK with nary a hiccup. But then I have also fired at least 3/4 of a gajillion lacquered cases through my 5.45 AK with the same zero issue reliability. Anecdotal evidence to say the least! I've heard many horror stories of people having major issues running lacquered stuff through standard 5.56 uppers. And even a few issues with running it through 5.56 chambered AK's. Can't recall hearing many complaints about running the polymer cased stuff through standard 5.56 AR's other than the usual complaints about how dirty Russian ammo is and the usual fouling associated with it and the business end of the gas piston in both AR's & AK's. Not sure how a completely polymer case might behave vs a polymer coated steel case though. Can't find much technical and test detail yet so am not sure what process they are using to build the polymer chains. Interesting subject though. Some days 1/2 of me wishes I had taken the chemical engineering path... The other half of me is always happy i didn't though! Besides, the fuddy duddies aren't likely to make it any easier for the rest of us to have access to this tech anyway. Maybe after the revolution?
If I recall correctly, there was a polymer cased 5.56 round that was peddled on the civilian market a few years ago. I recall that it had all sorts of reliability problems. The cases were blue in color. I think it was originally intended to be used as training ammo for the .mil. For now, I'll stick with tried and true brass. I like a lighter MG, though. The new M240 is supposed to be majority aluminum to cut weight. I haven't seen one yet, though.
