FN IAR
The FN IAR is based on the SCAR. It has a rate of fire of 650 RPM and weights in at 10.4 lbs.
FN IAR. Click to expand.
One very interesting features is that it switches automatically from closed bolt to open bolt depending on the chamber temperature. From FNH-USA:
Today FN offers the new Infantry Automatic Rifle (IAR), a unique, highly-adaptable, modular selective fire weapon system that fills the roles of both individual battle rifle and squad automatic weapon in one light, compact package. The magazine-fed FN IAR is capable of firing from a closed bolt in both semi-automatic and fully-automatic modes, yet automatically transitions into open-bolt operation in semi-automatic or fully-automatic before reaching cook-off temperature for a chambered cartridge.
I do not think the temperature switch would be electronic. Most likely there is a piece of metal that expands when heated and causes a switch from closed to open bolt.
Again, a bit thanks to Daniel Watters for pointing this out to me.
so are they going to give it a 100rd drum magazine?
gummywormz, yes, it is one of the IAR requirements.
Are you sure about that? There are a lot of problems that associate with them, historically. New gears have to be develop to hold the drums. I would hate to be the guy carrying three or four.
I think in the end the Marines will go with 40 or 45 magazines.
That was the original requirement.
“The IAR shall utilize a magazine with a capacity of 100 rounds (Threshold). The magazine shall permit rapid visual determination of the number of rounds remaining (Objective). Magazine Compatibility. The IAR shall accept and function with the current Marine Corps service rifle (the M16A4) 30 round magazines.”
https://www.fbo.gov/index?s=opportunity&mode=form&id=a8698386e4300ceee7bc1067a71dab5c&tab=core&_cview=0
this seems like a bad idea to me, but i just can’t put my finger on why. i think it’s the drums; the 100 rnd “nutsacks” are much smaller and easier to carry than the drums. i’ll be the first person to say that the SAW should probably be replaced, but i don’t think that the problem is the linked ammunition; that concept works fine in the 240 and the M2, although i was never a big fan of the Mk19. i mean, i wasn’t an armorer or a SAW gunner, i couldn’t tell you what the exact problem was, but it always seemed like it had ridiculously close tolerances for even a light machine gun, and it was undoubtedly a pain to disassemble, even harder than it’s big brother the 240. so if close tolerances are the issue, it seems like you’re just making that worse by relying on that capability in an assault-rifle-sized weapon. i just have this vision of a gunner walking around with these HUGE “mag” pouches hanging off of him…a lot of dudes just rolled the 200-rd drums which i imagine are, i believe, similar in size to the 100-rd circular drums, while the 100-rnd sacks are about, oh, 3 inches tall by 5 or so wide? it’s been two years since i’ve handled or seen one, keep in mind. but it seems like you’re getting half the ammo for double the weight/bulk, which is not a good deal in my mind. this just smacks of, in 20 years, somebody saying “it seemed like a good idea at the time.”
This is just my guess, and I have no military experience so take it for what it is worth, but I reckon the automatic rifleman will be carrying one, maybe two, 100 round magazine and a bunch of 30 round magazines. I think this is the case because those 100 round drums are not reliable. If one of those jams the rifleman will lose a significant percentage of the ammo he is carrying.
Has anyone used the Russian RPK ( http://en.wikipedia.org/wiki/RPK ) or one of the semi-automatic clones. How does it compare with the SAW.
The IAR is the RPK/BAR. That’s what the Marine wants, a true light machinegun that can keep up with the team. The SAW weight around 21 pounds. A fully loaded BAR is lighter then an unloaded SAW.
The Soviet got rid of their drums. The RPK-74 use box magazine, no drum.
Drum are unreliable and not durable enough for the battlefield. 100 rounds drum is over 3 times heavier then a 30 round magazine. The spring has to push three time weight at a speed that can keep up with the rifle cycle. That’s is very hard to do consistently. When a full loaded drum drop to the ground it can/will be damage. Any damage to the drum will effect reliability (Thomson’s drums are notorious for this).
I am surprise the Marine want drum magazine. Countless hours and money has been thrown at it over 100 years to make it work.
40 or 45 rounds magazine are the way to go IMO. They’ve proven to work.
“The fancier the plumbing the easier it is to clog up.” – Montgomery Scott
Looks like FN is trying to out-complicate HK. Just re-chamber the BAR or BREN to .223 (shudder) and be done with it.
i’m pretty sure the SAW is 15 lbs unloaded, i don’t know about the BAR, but in either case i concur with the spirit of jdun’s statement; the magazine/drum isn’t a good idea. our SAW gunners rolled two 200 rounders (still in the drum, usually), and usually a couple of 150’s, so about 700 rnds (if i remember correctly; again, not a SAW gunner, so i might be a little off) and maybe another drum in the pack on a foot patrol. so if you figure that the 100-rd mag/drums are about the size of the 200 rd drums, those take up a pretty decent chunk of the FLC…you could maybe put a couple of normal mag pouches up on top of the vest, but you couldn’t do a full UBL (7 mags), and 200 rnd drums on one vest, at least you couldn’t do it without pulling off other things like NOD’s, canteens, and the like. you might be able to squeeze another couple of 200-rnd mag pouches on top, i seem to remember some people doing that initially, although i don’t think it lasted very long. i think i’m pretty firmly on the linked-ammunition side of things, which i guess makes me pro-drum and anti-magazine (the difference, as i understand, is that the drum is for linked ammo and the magazine is spring-loaded?) although i’m sure there’s a more efficient way to handle linked ammunition, both on the side of the links themselves and the internal mechanism. i’m mystified by all this; it just doesn’t seem practical.
This comes from a deep part of the errornet rumor mill, but a reasonably reliable one so take cum grano salis
The open bolt/closed bolt cutoff switch in the FN IAR is not electronic. It’s functions by a little tab of metal (either a thermocouple or a shape-memory-effect alloy) that changes shape as the chamber heats up and flips the switch. Sort of like the mercury vial in a thermostat.
BACK TO THE FUTURE THE NEW BAR
The cause of the SAW reliability problems are caused by operator error. The the feed system of the M249 is far to delicate with lots of stamped metal bits that are easy to tweek out of alignment. It just takes one laps of concentration in the heat of battle to turn a very effective problem solver into 14lbs of useless. It make me cringe every time I think of Gomer Pile looking confused while he tries to load a new belt in his shiny new toy with the bolt forward… clunk… clunk… “Why won’t this thing close?” clunk… clunk… “Maybe if I slam it really hard.” CLUNK… CLUNK…
As for the magazine vs. linked ammo debate, why not both? How about a modular weapon system that can be configured as magazine only, belt only, or both magazines and belts. There is only one real option for a M249 companion/replacement, the Shrike Modular Weapon System. Light weight, dependable, field configurable and all mounted on the familiar M16/M4 lower receiver. What more could you want? Add the open bolt/closed bolt fire controls of the LWRC IAR or the FN IAR and you would have the perfect IAR contender. But why stop there? With the Shrike’s belt feed capability, it could replace the M249 entirely. And with no stamped metal bits to tweek, it may even be Gomer friendly.
this just doesnt seem like the most bang for the buck. especially FN’s scar variant, quick change barrel? ha, 6 torque screws that need a specially pre loaded torque tool? oh and if you think spec war actually likes the thing or chose it ask your nearest seal, alot of politics kept the chosen 416 out of their hands anywhoo atleast colt put on a quick change barrel. it all seems like fore runners for whats to replace the m4, the scar, 416 or another colt, but if this is truely a supressive fire weapon these seem to be horrible choices, i like the concept of the ares shrike, same familiar m4 platform but either belt fed or magazine fed, and if its true the saw is a big target the shrike is cosmetically identical to the next guys m4 so spend some money making it soldier proof and bam, good to go.
Steve
Ditto on the RPK question. The first thing that popped into my mind upon hearing of the USMC IAR project, was that the RPK is exactly the sort of weapon the fills the IAR role.
As far as box vs drum feed, the Chinese and Singapore seemed to have been happy using drum fed squad automatic weapons, unlike the Russian RPK experience. I understand the Chinese made drum for the RPK is somewhat different and much easier to load and unload than the Russian design.
I have also heard rumors that the Russians experience from fighting in Grozny influenced them to prefer 7.62×39 caliber weapons to those in 5.45mm. Supposedly the 5.45mm was inferior for shooting through walls, floors, ceilings and other typical urban cover. That sort of area fire would seem to directly reflect on caliber selection for a squad automatic.
(Maybe it’s a good thing for the new Iraqi army that 7.62×39 RPK remains the squad automatic weapon?)
I appreciate the problem the USMC is trying to solve with the IAR. The USMC fire-team needs an automatic weapon suitable for suppression and the assault roles, given the limited quantity of people in a fire-team. The M-249 is too clumsy for use in assault.
I don’t see the need for a magazine fed SAW. The role of the SAW is to lay down suppressive fire, lower capacity mags mean more mag changes. The more mag changes, the less time the weapon is firing. It might take a little longer to put a new belt in a 249 (I hate the 249) but at least there will be 200 rounds there when your done.
You don’t need a fancy thermostat (that WILL break) to switch from closed bolt to open. What’s the need of a SAW to fire from the closed bolt anyway? Its not meant to be a precision weapon, It just needs to put down suppressive fire. If the barrel heats up you can just change it on a 249.
I think this is a waste of time and money for nothing. Why did we stop using the BAR in the first place? Fire Power!! I think we are better served with linked ammunition.