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View Full Version : Is a carbon fiber AR lower in our future?


artoaster
04-21-2012, 7:57 PM
As someone who sees carbon fiber becoming more accessible in many types of sporting goods and automotive applications, why isn't taking over as the material for AR lowers?

It seems there have been attempts by Vulcan, Bushmaster, Plum Crazy and New Frontier into the alternative composite materials but I don't think they been really successful yet.

What are the pros and cons? I wonder only about carbon's ability to have good strength where drilled and not wear on the holes for the trigger, hammer, safety, and the front and rear take down pins where you would not want to see enlargment or elongation occurring.

????

TNP'R
04-21-2012, 8:07 PM
Me personally I wouldn't buy one, nothing against them I just like the feel of metal, I'd buy a Glock but not an Ar-15.

Intimid8tor
04-21-2012, 8:11 PM
Not likely. Too hard to mfg and too expensive.

I do think we will see additional polymer lowers with different materials. Glass filled nylon and other composites.

Redchevyman
04-21-2012, 8:16 PM
I have been hearing nothing but good reviews on the New Frontier complete lowers. I will be buying a few as soon as my local dealer gets them in stock.

bohoki
04-21-2012, 8:16 PM
i dont see the reason but if someone wants one someone will make one

ADAM
04-21-2012, 8:20 PM
no reason to make them,

ANG Tactical
04-21-2012, 8:27 PM
Seems to just be more cost effective in aluminum with no significant difference.

Moonshine
04-21-2012, 8:35 PM
Bushmaster has made carbon fiber lowers for a long time, the Carbon-15. Just hasn't caught on prob cuz the military doesn't use it. It's more expensive than aluminum though.

Polymer pistols are pretty much the standard at least with law enforcement so its prob not a stretch that polymer rifles such as the new frontier could catch on with agencies due to low prices. Carbon fiber being more expensive doesn't look as likely.

shooterdude
04-21-2012, 8:42 PM
Reproducing a metal part in composites is not always the best idea for many engineering reasons but making a new design that takes advantage of what composites offer is brilliant. For instance, the Beretta ARX-160 is just such a concept.

Expect to see new designs based upon polymer/composite materials but don't hold your breath waiting for reproductions of metal parts in composites.

bohoki
04-21-2012, 8:53 PM
Bushmaster has made carbon fiber lowers for a long time, the Carbon-15. Just hasn't caught on prob cuz the military doesn't use it. It's more expensive than aluminum though.

Polymer pistols are pretty much the standard at least with law enforcement so its prob not a stretch that polymer rifles such as the new frontier could catch on with agencies due to low prices. Carbon fiber being more expensive doesn't look as likely.

uh no that is not carbon fiber that is fiber reenforced zytel

carbon fiber is a fabric impregnated with resin that when baked turns hard and has that spiffy pattern as a benefit

Josh3239
04-21-2012, 9:06 PM
I had a Carbon 15, I liked the lighterweight of it. But aluminum was calling. Besides, I don't think I'd feel comfortable treating the carbon fiber roughly.

SwPx4
04-21-2012, 9:08 PM
Would be interesting, but don't see it happening.

Aznatama
04-21-2012, 9:12 PM
carbon fiber is a fabric impregnated with resin that when baked turns hard and has that spiffy pattern as a benefit

Not always. you can reinforce plastic with any type of fiber, whether it's fiberglass, carbon, or kevlar.

you're talking about woven carbon sheets, like the very top layer of a CF hood or whatnot. that would not make any sense in a firearm. You'd probably want some sort of fiber reinforced plastic.

fusionstar
04-21-2012, 9:22 PM
still waiting for my super stiff, ultra light graphene nano tube barrels to come in. 10000 fps anyone?

bigdawg86
04-21-2012, 9:29 PM
I don't think carbon fiber lower would have and more functionality issues than a aluminum lower... It seems counter intuitive that something with less mass can have same or better durability, but if they can make full carbon mountain bike frames, car chassis, etc then why not firearm component? There is a huge difference in types of CF and the stuff on the hood of some rice burner probably wouldn't make the cut

jcjt
04-21-2012, 9:30 PM
Some initial thoughts on this topic, assuming working with composite sheets (I have no experience working with fibers, just designing with aluminum )

-controlling tight tolerances on wrapped/laid cf sheets must be tough
-inserts for threads in fibers are not as strong as tapped aluminum material
-CnC aluminum lowers is probably less pita than laying fiber in a mold for something with small features such as a lower
- cost for tooling and training people for a new mcg process outweighs the stability of the already established machining process. They already have the machines and machinists with experience to make a product. Why change the process when there might be financial risk involved?
-I doubt the mil spec has defined anything for a composite lower.

smarter
04-21-2012, 9:31 PM
http://www.sitemfg.com/
they've been making barrels for paintball guns for several years now. I wonder if we can perhaps see smaller diameter barrel wrapped in carbon fiber.

TreeHugger
04-21-2012, 9:34 PM
Call me old fashioned, but I prefer mine being CNC-machined from a nice big chunk of billet 7075-T6, the cold steel just feels so warm and fuzzy to me.

BroncoBob
04-21-2012, 9:47 PM
Got a carbon 15 sitting in the back of my safe. Just to remind me what it was like back then. Not worth much but for memories of a time past by.

biscuitbarrel
04-21-2012, 10:06 PM
Technology always improves. It will happen, in time.

FourLoko
04-21-2012, 10:09 PM
http://www.sitemfg.com/
they've been making barrels for paintball guns for several years now. I wonder if we can perhaps see smaller diameter barrel wrapped in carbon fiber.

check this out:

http://www.christensenarms.com/firearms/tactical

Merc1138
04-21-2012, 10:16 PM
http://www.sitemfg.com/
they've been making barrels for paintball guns for several years now. I wonder if we can perhaps see smaller diameter barrel wrapped in carbon fiber.

1. A paintball barrel doesn't undergo anything close to that of a gun barrel
2. A paintball barrel isn't rifled(well, you can buy rifled paintball barrels but they do jack squat)
3. Companies have been making .22lr and other caliber guns using bore sleeves and wrapping them in other materials for a while now.
4. Christensenarms makes one in 5.56 and it costs an arm and a leg.

glockwise2000
04-21-2012, 10:31 PM
Carbon Fiber?

I am not sure. But I will not deny that in the future there might be one. New Frontier's polymer is doing good though. A lot still doesn't believe them and continue to be in denial that a plastic lower still exist. I think they are great though.

For me, the more choices, the better.

kalbos
04-22-2012, 4:58 PM
are we talking carbon fiber or polymer? NFA and the plum crazy lowers are made of polymer. Different material than carbon fiber.

I have LW-15 from new frontier. Not crazy about the polymer fire control group stuff. I had 800 rounds through mine and it started to double fire on me. I had an early lower and they supposedly fiexed the problem after #2000 but I replaced mine with a Daniels Defense trigger control group and I have had no problems after that.

Moonshine
04-22-2012, 6:52 PM
Speaking off the old Cali carbon-15 I thought all of those had the plate popped out by now or were replaced with stripped open mag well lowers. Props on the nostalgia factor!

HK Dave
04-22-2012, 7:09 PM
Personally I think a carbon fiber lower serves absolutely no purpose. A lower is already extremely light to begin with. How could carbon over possibly improve on anything?

Haplo
04-22-2012, 7:30 PM
What improvement would carbon fiber offer? Stripped lowers don't weigh much as it is, so weight savings is of negligible benefit. Durability isn't a concern either. There aren't any obvious benefits to it.

TNP'R
04-22-2012, 7:32 PM
Wouldn't carbon fiber cost more as well? Compared to a polymer lower?

speedrrracer
04-22-2012, 8:32 PM
Not always. you can reinforce plastic with any type of fiber, whether it's fiberglass, carbon, or kevlar.

you're talking about woven carbon sheets, like the very top layer of a CF hood or whatnot. that would not make any sense in a firearm. You'd probably want some sort of fiber reinforced plastic.

Yes, always. CF is always a fabric that must be impregnated with resin, and the curing process will result in the lovely stiffness that makes CF so amazing.

Baking is optional, but the benefits of a post-cure on epoxy is well-documented. No reason to avoid it.

Fiber reinforced plastic IS fiberglass. AND carbon fiber. AND kevlar. Any of those fits the definition, and others as well.


inserts for threads in fibers are not as strong as tapped aluminum material

Too broad a statement. Inserts in composites can be "stronger" or "weaker" than tapped aluminum -- the devil is very much in the details. I use quotes because composites aren't measured in strength, so it's incorrect to apply those terms.

To the OP's question -- CF lowers can exist, but there's not much point. Sure, you can save a few ounces from an aluminum lower, but the cost will skyrocket.

Drilling the finished CF is not a problem. You fill the hole with a plug of fiber-reinforced epoxy, and then drill a smaller hole in the plug and epoxy in your insert. Do it correctly and that insert will handle crazy stresses. Far beyond anything a lower would ever be spec'd to endure.

Also, just because composites can achieve extraordinary things does not mean all composites are extraordinarily amazing for all purposes. They must be built in specific ways to achieve certain things. For example -- imagine a piece of paper. If that paper were made of carbon fiber, it would be crazy stiff along the 8.5" or 11" axis (you could stand on it if you had perfect balance so as not to apply any torsional stresses), but along the thickness axis (1/100th of an inch or whatever it is) it would be so weak you could easily shatter it in your hand.

So, for a lower, in places where the wall is not relatively thick or well supported, there could well be "strength" issues. The stiffness of composites is directly correlated to beam thickness. You might therefore have to adjust the dimensions, which could lead to issues downstream where other applications assume standard exterior dimensions, for example.

Harrison_Bergeron
04-22-2012, 8:35 PM
What improvement would carbon fiber offer? Stripped lowers don't weigh much as it is, so weight savings is of negligible benefit. Durability isn't a concern either. There aren't any obvious benefits to it.

Less weight is less weight, race ready road bike components made of aluminum are not heavy by any means, yet those who are truly competitive will ditch all of those aluminum parts for carbon to have a bike they can lift with one finger. Weight aside, there are other benefits to carbon, it does not transfer shock nearly as much without sacrificing rigidity. These together could potentially translate into less fatigue for people who carry all day and shoot a lot, like soldiers.

edwardjames
04-22-2012, 9:18 PM
sounds good for a light weight range gun. but i wouldn't bet my life on one if i had to pack it around with me in a harsh environment. id imagine an aluminum lower would be able to handle more punishment that a carbon fiber lower.

peter95
04-22-2012, 9:48 PM
simply because our lowers are not that heavy. If you think it is, you should work out.

peter95
04-22-2012, 9:50 PM
Less weight is less weight, race ready road bike components made of aluminum are not heavy by any means, yet those who are truly competitive will ditch all of those aluminum parts for carbon to have a bike they can lift with one finger. Weight aside, there are other benefits to carbon, it does not transfer shock nearly as much without sacrificing rigidity. These together could potentially translate into less fatigue for people who carry all day and shoot a lot, like soldiers.

Im thinking if the whole rifle was made of Carbon Fiber, then yes, you will be able to see a huge difference, but really think about it, its just a lower... Really not a huge weight issue.

artoaster
04-23-2012, 9:45 AM
If weight savings isn't significant for lower to be made of carbon fiber or other composite then I would wonder about just having a carbon wrapped lightweight steel barrel with a free float handguard, pistol grip and buttstock made of carbon fiber and seeing if weight could get under 4 pounds for carbine.

morthrane
04-23-2012, 5:33 PM
Carbon fiber (and fiberglass, etc.) does not lend itself well to mass production-- not like cast/forged/milled metals, or molded polymers. Most kinds are UV light sensitive and need some kind of paint coating to protect the CF. CF might be immensely strong and light, but it is brittle compared to typical steel and aluminum alloys... and when it fails, it fails catastrophically. (see this in motorcycle wheels-- a steel wheel will dent, an alum will crack, and a carbon fiber wheel will disintegrate from equivalent destructive impacts)

CF is for performance at the expense of other characteristics like durability. Look at how much it is used in serious offroading vehicles for example-- as far as I know, barely at all.

As far as an AR15 lower goes, I also suspect it isn't well suited for CF layup. Most CF motorsport parts I've see have metal inserts in the layup for metal axle points (e.g., takedown and trigger group pins) rather than just drilling directly into the CF weave. It would probably be easier to make a AKM receiver out of carbon fiber than the AR15 lower...

Bottom line-- I don't see the benefit. I don't see engine cases made out of CF in even the most delicate high performance race vehicles, so why would you want to do the same to the firearms-equivalent receiver? It would make far more sense to make the ancillary gear like the buffer tube/stock, grips and guards, and other stuff out of CF. Carbon fiber magazines would be pretty trick.

How about a bolt action scout rifle with a CF stock/chassis?

tacticalcity
04-23-2012, 5:48 PM
Unlike a Glock there is a lot of weight to an AR upper. Weight that translates to a lot of forces as it twists and contorts as you run. It is also a lot more likely that an AR will smack into the ground hard, and have to support your entire body weight several times during a CQB course or CQB or Combat style training day. Lots of examples of plastic lowers failing under those conditions. Plain old range plinking, they do fine.