I think the pictures are pretty self explanatory.

[img]http://www.thermaldynamics.com/pictures/SS04/HKM4-4.jpg[/img]
Notice the gas key is no long the key, it is soild and it is used by the piston rod to force the carrier back into the buffer tube. the Bolt also has no gas ring.

[img]http://www.thermaldynamics.com/pictures/SS04/HKM4-5.jpg[/img]
Carrier exhibit no gas relief holes.

[img]http://www.thermaldynamics.com/pictures/SS04/HKM4-6.jpg[/img]
The working end of the gas system.

[img]http://www.thermaldynamics.com/pictures/SS04/HKM4-7.jpg[/img]

[img]http://www.thermaldynamics.com/pictures/SS04/HKM4-8.jpg[/img]

[img]http://www.thermaldynamics.com/pictures/SS04/HKM4-9.jpg[/img]
Close up shot of the HK manufactured receivers.  The Made in Germany will be replace by Made in USA once the Georgia plant is up and operational.

[wow]
No matter what anyone says, that thing is one badass piece of hardware. Very cool pics. If I had gone they would have had to clean my drool up off the floor.

I like that they used the Vltor stock, but that shiny purple ARMS knock-off mount? [stick]

Nice pics, Chen.  Thanks for sharing.

I've seen a couple shots of the gas piston setup before.  Is that the piston spring?  Does it have a cover and this a 'cutaway' version for the show so that you can see the piston or is it actually exposed under the handguards like that?

Its exposed under that handguards if I remember correctly. Chen?

It is as it is under the handguard, I requested for the handguard to be removed for a photo op.

The piston is just like the G36 piston and the op rod is not to far from the G36 rod.  

20,000 round barrel life, but I would not trust any gun not to be cleaned for 20,000 as stated by HK.  they had the brass from the demo on Wednesday, all the casing picked up from the ground are still shinny new, not to much carbon build up inside the receiver.

I wonder if that would work with a RAS?

[b]Will the uppers work on ANY AR lower? [/b]

Gas or piston, that sucker still needs an ejection port cover.

I'll pass.

needs 2 things before i'll buy one

1. free floatable barrell
wether it be RAS, ARMS whatever
no free float, no buy

2. dust cover.
if it dont work with one, it dont work with me.

What Frisco and Lumpy said.

I don't see how HK justifies no ejection port cover when they changed nothing internally to increase relibility as far as I know.

Also, the spring above the barrel (I haven't figured out what exactly it does on the HK). Isn't that the same basic problem that the ZM weapons uppers have ( a spring exposed to heat that will lose temper due to heat created by very rapid fire or full-auto "abuse")?

I'm still looking for the advantages of this "system" other than having to clean slightly less often.

If you look at the pick of the carrier, it's pretty obvious that more material on the carrier comes in contact with the inside of the upper receiver.  Seems like this would make matters worse in a sandy environment.  But what do I know, I am sure HK did plenty of testing and maybe the carrier does work better in such conditions.

First of all, thanks for the awesome pics SMGLee!

I like it--the only flaw I see in it is no ejection port.  Wonder why?

Needs a dust cover. Seems stupid to have removed it. Free float bbl. would be nice. I read on the HKUSA website that a monolithic upper is "...in the works", which could be intersting. Just replace the picatinney gas block w/ smaller, lighter G36-style one & extend the monolithic rail out over it, a la LMT MRP.

Probably the biggest question on my mind concerns why they didn't use a stronger return spring on the piston rod assy & eliminate the rear buffer tube spring & buffer assy. I'd wager this setup allowed them to keep the stock handguards, but it still seems ludicrous to retain the rear buffer & spring when it could be eliminated. Weight looks to be a factor - the one w/ the 10" bbl. & milled-from-billet HG rail looks as if it could weigh ~10-12#. Quite a bit for a carbine.

What does it say on the other side of the receiver?

Very cool pics, thanks!

That detachable rear sight is rather interesting...

From the SL8 manual:

"The gas piston drives the bolt assembly rearward via the push rod. The return spring on the push rod returns the rod to it's starting position."

So it keeps the rod that pushes the bolt back snug against the gas piston (resets the piston also). At least that is what it does on the G36/SL8/XM8.



I'm really not aware that this is a problem and cannot see how it could be any problem over any other design that has any kind of springs over the barrel. The ZM design actually has a heat sheild between the barrel and the spring. The G36/SL8/XM8/M1A/AK and many others all have springs close to the barrel, many of which are even closer than the ZM and are not sheilded, and they don't have any problems. So I can't see any issues with  the HKM4s return spring being above the barrel.

Just to show you the seriousness of HK's turpitude of the M4, they go ahead and use the Larue mounts that definitely are an adbomination of ARMS quality products.

Keep it!

Hey Chen, I'll hand back "da man" title to you now.

I can't wait.

Some one at HK is probably friends with Mike LaRue and used his product as a favorite.  I have to agree, the LaRue products seem to be a blantant rip off of the ARMS product.  and as far as quality, the LaRue is no where near the superb quality of the ARMS units.  

You are way too kind, I am still not da man.  I am just a poser. [:)]

Doesn't Pat Rogers prefer the laRue mounts?  I think I remember him posting that he thinks highly of them.  But yeah, they are an ARMS rip-off.

If memory serves me there was a "Rhino"??? conversion of the AR's gas system to one simular to this about 20 years ago. Didn't catch on then and doubtfull it will catch on now.

I'm with Lumpy, I'll pass.

Man that is distinctly HK.  Those fire control markings look out of place.  [:)]

I like the fire control markings.  Its probably the only thing I like on it right now without actually firing one.  

SMGLEE, is tht a heavy barrel on the short HK?

And, those HK Black Rifles sure are...well they're very BLACK! Any idea of what kind of finish?

Anyone else notice that the HK uppers have a relief cut into the RIGHT side of the upper receiver for the charging handle latch?

I would bet that HK plans to offer dedicated left-handed charging handles with the latch on the right side.  This would allow operators to change the configuration to suit their needs.

Josh

SMGLee did the HK guy say that in the production version that they were going to keep the dust cover off?  If you look on the HK website the pics on the HKM4 being tested there have dust covers and a fixed front post with a standard removable carry handle.

Have to agree 100%
I thought the pictograms were a nice touch, distinctly HK but still right at home on an AR as well.



I asked if the DC's were skipped just to get the rifles ready for SHOT and speed things up or if they were planned that way.
An HK rep. said, the DC's were going to be left off of production models, because "tolerances were so tight, no dirt was getting in there" and that they ommitted the FA notches forward of the rear because "they weren't needed and were just another place for dirt to collect".

Needed or not, on a Rifle of HK's Stature/Rewp./price, needed or not I want a DC, period.  It might be overkill, it might be "useless" but it would be icing on my cake and would put my mind at ease.  Like isaid for the $$$ I want the utmost attention to every last detail.

/S2

I think this is the best improvement to the M16 design to come along in decades. No longer will the thing crap where it feeds, grains of dirt or sand are not an issue, and overall the system looks pretty sturdy. My only reluctance when I bought my AR was the gas system after experience many failures in the military and now that is fixed.

Thanks HK!!!

I REALLY want one too!
But with a friggin' dustcover or it's a no go.

From the pics of the production run, it doesn't  have the pivot pin holes for a dustcover, and even if they were there, it wouldn't work because the Bolt carrier has NO detent cut for the dust cover notch to properly open or close.

I don't know if this link has been posted yet or not, but it gives some good info -- scroll down to the bottom to get the specs and some pretty cool pictures of the gun...

[url]http://www.hk-usa.com/pages/Military-LE/rifles-carbines/m4.html[/url]

Gunz

[img]http://www.thermaldynamics.com/pictures/SS04/HKM4-4.jpg[/img]

   For a gun that doesn't require cleaning or lubrication (and at a trade show no less) that bolt is sure making his hand dirty.

   I also noticed claims of being amibidextrous, but the fire selector lever is flat on the right side like any AR. I figure they would have used their HK selector lever to go along with the pictos.

One last thing, and I might have missed this being commented on before, but with the bolt:
1.) No bolt rings
2.) Is that the firing pin retaining pin next to the bolt cam pin? Looks better than the cotter pin in all of our ARs.

   Overall I would be very interested in trying one out and seeing if there is a noticable increase in accuracy. It seems they are touting more on reliability than accuracy.
I'm no competition shooter, but I like to think I am a decent shot.

   Since I'm a civilian now I won't be dragging my rifle through the mud (unless I'm being chased by hordes of zombies/wtshtf) so simply getting a more reliable rifle for range shooting would probably not be worth the $2k price tag I expect to see for this bad boy. I have never had reliability issues when plinking.

   Not having to clean it for 20,000 rounds... I don't know where they learned about weapon maintenance, but I could never put my AR away without cleaning it. That's just wrong!! Like not wiping your ass after shitting in my book.

   However, if down the road ar15.com gets their hands on one for a giveaway, or even just a handful of mags, I will probably get a couple more memberships going... one for my wife, my 6 months old son, my dog... anythign to increase my chances.

   [edit] Also, I would assume they are more than likely going to be making them in the same factory as the XM8 in Georgia, so import laws won't be an issue, which will hopefully put them in our local gun stores.

    Wonder if they plan on chambering it in 6.5mm and/or .308.