[Skunkabilly]

...are they really made out of carbon fiber? :o They just look gray to me.

[Chris Rhines]

Supposedly, they are made out of "Carbon-fiber reinforced polymer." Or maybe "Polymer-reinforced carbon fiber." I can never keep it straight.

- Chris

[Skunkabilly]

What the heck is reinforced polymer? A plastic coated shell over a carbon fiber frame??

[Correia]

Either way, the SLC SWAT team ditched their UMPs after a year of hard use because they kept breaking the stocks. Carbon fiber or not. :)

[Handy]

It is likely "carbon reinforced polymer", just as Glocks are "nylon reinforced polymer". Essentially, it's just small fibers floating in the goo that goes in the injection molder. The little fibers reinforce the plastic, like iron slivers in concrete.

No shell, no skeleton.

If you break up your breakfast cereal, you end up with "wheat fiber reinforced dairy product".

Impressive, no?

[Schuey2002]

They just look gray to me.
Beats having a white one like German gunowners get.. :neener:
http://home.c2i.net/johnhe/sl8_r.jpg
This SL8 needs to be dunked in a bucket of hot water & black Rit dye..:D

[Skunkabilly]

So technically my organic breakfast cereal is carbon fiber? Coool!!! :D

Correia, any other reasons? The UMPs have fixed stocks so I don't think that problem will carry over unless it's the receiver itself that breaks?

[T.Stahl]

Beats having a white one like German gunowners get.. :neener:

That's not white, that's winter-camo.
At least I can use G36 mags (if I could afford them).

And since this month HK is offering the SL8-5, which looks like the SL8-4 the Norwegians get.

[gun-fucious]

http://www.rtpcompany.com/info/molding/long/#comp

http://www.me.dal.ca/~dp_99_1/progress1.htm

http://home.c2i.net/johnhe/g36.html
Materials

The extensive use of synthetic materials is among the most noteworthy characteristics of the G36. H&K were pioneers in the use of synthetic materials back in the 1960s and 1970s, and with the G36 they prove that they still are. The G36 is the first production rifle to have a receiver made from a polymer compound. In fact, the only metal parts are the barrel, gas piston, bolt assembly, mainspring, retaining pins, receiver rails and a number of minor components inside the trigger housing.

Receiver, stock, forearm, carrying handle and trigger housing are all made from a special high-strength injection-moulded polyamide (apparently Nylon 66), reinforced with microscopic carbon fibres. This material combines high resistance to corrosion, wear, chemicals and radiation with low weight, great strength and high dimensional stability.

The receiver has moulded-in stainless steel rails, on which the bolt assembly reciprocates. All metal parts subjected to friction are given a special coating, which also helps protect against corrosion. The cold hammer forged barrel is made from corrosion resistant chrome steel, internally chrome-lined and externally protected by a tough, matte-black oxide finish.

The use of synthetic materials results in a rifle with a very low weight and a high degree of resistance to wear and corrosion. Still, it is wrong to think of synthetics as the ultimate in construction materials. The G36 is robust, but it is not unbreakable. The stock, in particular, has received some criticism for being prone to breakage. This is of course unfortunate, also because the user will sometimes have to rely on his rifle as a thrusting or striking weapon. We believe, however, that some of this criticism is a bit unfair, since the G36 tends to be measured up against its predecessor in the Bundeswehr, the much heavier, fixed-stock G3A3. It is obvious that low weight and great strength are conflicting demands, and in our opinion the G36 stock is an acceptable compromise. Nevertheless, a few grams of reinforcement put into it would not do any harm.

Low weight is essentially an advantage in a weapon of this type, but we suspect that at some stage, the engineers at H&K became somewhat fanatical about saving weight. This may be the reason why they initially chose not to incorporate a heat shield inside the forearm. As a result, the forearm overheated very rapidly, a few magazines of rapid fire was enough to make the rifle very unpleasant to hold with bare hands. This problem has now been rectified. New rifles are supplied with a redesigned forearm, which is fitted with an internal heat shield, as well as external hardpoints for mounting of accessories.

There has been some scepticism concerning the sturdiness of the polymer receiver. Clearly, it is not as rigid as a typical sheet steel or cast aluminium construction, but this is not necessarily a disadvantage. When subjected to stress, the polymer compound will flex reversibly rather than dent or crack. Although not verified, it is probable that the amount of stress that is required to cause permanent deformation of the G36 receiver is equal to or greater than that for designs employing traditional materials.

Around the beginning of 2002 there were several reports of the polymer in the SL8-1 cracking up. There were never any reports of similar problems with the G36 or the other versions of the SL8. The cracks invariably appeared in the very foremost part of the trigger compartment, running vertically along the seam below the bolt catch. A design flaw turned out to be the cause. The modified single-feed bolt of the SL8-1 struck the bolt catch on one side only, forcing it to twist and travel forward enough to fracture the material in front of it. After some delay, H&K released a replacement bolt catch with an enlarged contact surface, which alleviated the problem. New rifles are now fitted with the improved bolt catch. Rifles with the old bolt catch can be returned to H&K for replacement of this item, or if the crack has already appeared, replacement of the whole buttstock/lower receiver.

[Handy]

Well, that was certainly long.

I'm not sure where they get off saying that it is the "first polymer receivered rifle" when the Nylon 66 has been around forever. Centerfire, possibly.

Basically, HK used an AR18 mechism, where the bolt carrier rides on rails, to serve as the G36 basis. Since all the action takes place on those rails, the receiver material is... immaterial.

In other words, you could probably make a similar rifle out of paper mache, if everyone promised not to spill their beer on it. In the case of the AR18 and G36, the receiver body is there to provide a strong moring for the stock, trigger group etcetera. And has the G36 done that? Reread section on cracks.


Basically, when someone comes up with design that utilizes much lighter strength materials, it's probably because they found a way to avoid stressing those materials at all. That's the notion behind the AR15 bolt system too.

There is little "revolutionary" about the G36/SL8, aside from it being the cheapest decent assault rifle ever.

What did Gaston say? "Disposable guns for disposable soldiers."

[Correia]

Skunk, I don't know the specifics. All I know is what one of them passed on to me. He said that the plastic was breaking and they were going back to their MP5s and Galils. I can try and find out.

[Skunkabilly]

I can try and find out.


No hurry, I still haven't heard back from the potential employers yet.... :(

[Kobun]

The stock on the G36 break too easily.
There were a bunch of stocks that broke in the cold in Afghanistan, and here, the military stocks stocks (:p) for the few units that has some G36's.

[Chris Rhines]

The problem with the G36/UMP stocks appears to be not one of weight, but one of design. They skeletonized the stocks to within an inch of their lives, probably in an attempt to save weight (or make them look kewl...)

Like the article said, add a few grams of material and worry less about ounces.

- Chris

[Schuey2002]

At least I can use G36 mags (if I could afford them).
In roughly 17 months I'm going to be swimmin' in $50 30 rd. G36 mags.. Wait and see. It will happen. :neener:

[Spark]

Yep.

Just under two years, ladies. Be patient... I'm saving my money now.

[JOE MACK]

Hah, I'd just put in the AR-15 magazine kit and buy a bunch of 20 rounders. :neener:

[Tamara]

Just under two years, ladies. Be patient... I'm saving my money now.

I'm givin' 9-1 that we get a new, more draconian ban that bans "assault weapon" possession by those under the age of 21 and ends all importation of "large capacity feeding devices".

Care to save your money to cover that bet instead? :(

[Schuey2002]

I'm givin' 9-1 that we get a new, more draconian ban
I'll take those odds. Where do I send a 20 dollar bill ?? ;)