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View Full Version : Thinking about carbon fiber tubes


Stone
05-21-2011, 10:33 PM
Well, they aren't the coolest looking, but they do seem to be significantly lighter and hence more practical than the aluminum tubes.

There are a number of options. Seems like the main ones are Precision Reflex (PRI) (http://www.pri-mounts.com/mm5/merchant.mvc?Screen=CTGY&Store_Code=PRI&Category_Code=308_ACC), CarbonArms.us (CarbonArms.us), Lancer Systems (http://www.lancer-systems.com/PDFs/LCH_Flyer.pdf), Clark (http://www.clarkcustomguns.com/clk750.htm), DPMS (http://www.dpmsinc.com/store/products/?prod=2095),

I like the venting tubes because they offer the option of putting on mounting rails as well as better cooling. They also look a little better (http://photos.imageevent.com/smglee/ss11/huge/P1070423.jpg).

It seems there are two basic methods of installation, one is to replace factory barrel nut with a custom one and glue the tube onto it, the other is to use a receiver extension. What are the pros and cons of these two attachment methods?

The PRI tubes are probably the most common yet they have apparently the highest weight. The specs I've found show PRI tubes weighing 11.2 oz with rails removed and aluminum nut, but as much as 20 oz with the rails (ie, heavier than a lot of aluminum rail systems). In contrast the Clark only weighs 6.2 oz, Lancer weighs 6.6-9.9 oz depending on length, the Carbon feather say they weigh only 4.3 oz (not including nut).

It's hard to trust these weight measurements as it seems that a significant portion of the weight comes simply from the nut and this is sometimes counted and sometimes not counted in the weigh-in so I'm not quite sure how to compare them. I don't know if the weight of the actual tube is the same or different...maybe the lighter ones use thinner, less sturdy carbon fiber?

Anyway, I'd just like to hear some first hand opinions

1911su16b870
05-21-2011, 11:12 PM
I built up a 16-in DD lightweight barrel to a Clark CF handguard and it is light. Putting glass on top of it makes it heavy...

I also have a PRI Mk12 style setup. 100% quality PRI stuff!

bombadillo
05-21-2011, 11:30 PM
My favorite rail by far that was round and vented was a VTAC from JP. It has rail options at just about every point you could ever want, long or short rails from 2 notch rails to full length rail. Its relatively small and easy to get a grasp on, easy to install and take off to work with and clean things. I would go VTAC again in a heartbeat if I were doing a free floated build.


http://jprifles.com/1.4.4_hg.php


http://jprifles.com/photos_new/handguardcomp.jpg

http://jprifles.com/jp_galleries/176.jpg


And some final eye candy for the push.

Capita159
05-21-2011, 11:59 PM
It seems there are two basic methods of installation, one is to replace factory barrel nut with a custom one and glue the tube onto it, the other is to use a receiver extension. What are the pros and cons of these two attachment methods?


Well, i only dealt with the DPMS "carbine length" carbon fiber tube for AR15 rifles. I bought it to mount on my girlfriend's Bushmaster carbon upper. But the plan fail, because I fail to check the size of the barrel nut. Bushmaster's carbon upper uses a slightly larger diameter barrel nut. So I end up installing it on my other rifle.

A picture of the rifle with the tube before it was sold, 6lbs and 11oz without magazine and red dot.
http://farm4.static.flickr.com/3657/5709460138_24886e770b_z.jpg

Pros:
1. weights 4.9oz. "and not 6oz." complete with barrel nut
2. very durable
3. stay cooler than metal tubes
4. looks cool

Cons:
1. the tube measures over 7.2" in length so therefore I had to sand off a bit to fit it with a YHM gas block front sight.
2. Once glues, there is no going back, so don't put it over a low profile gas block otherwise you would need to saw off the tube to remove or modify the barrel.
3. no sling mount on DPMS CF tube

I ended up putting an Apex Machine 9" tube on her rifle making it weight 4lbs and 14oz. without magazine.

Here is a cheat sheet for hand guard weight as well as other AR parts:
Aftermarket AR15 parts weight sheet (https://spreadsheets.google.com/ccc?key=0Ajl2UPK0UHPsdHNVX2tBak9OS29HR2ZrRFBhUVpYM VE&hl=en#gid=0)
rail weight sheet (https://spreadsheets.google.com/pub?key=pwswheghNQsFnUZMkZNF2DQ&output=html)

rareair
05-22-2011, 1:30 AM
If you want light weight, I'd suggest looking into the TRX-series of hand guards from Troy Industries (http://troyind.com/battlerails/trx-battlerails). They are the manufacturers for the Viking Tactics/JP hand guard mentioned above as well.

Stone
05-22-2011, 7:39 AM
bombadillo, the JP tube is not carbon fiber. Their 12.5" tube weighs 15 oz without any rails on it. That's even heavier than most aluminum rail systems! Compare that for example to the Carbon Fiber tube of the same length that only weighs 4.4 oz.

The Troy TRX extreme are the lightest aluminum rails I've seen, and something to consider, but still seem about twice as heavy as the carbon fiber tubes (with the exception of PRI, which have ridiculously heavy CF tubes for some reason).
7.6" = 7.52 oz
11" = 9.93 oz
13" = 11.43 oz

bombadillo
05-22-2011, 8:45 AM
bombadillo, the JP tube is not carbon fiber. Their 12.5" tube weighs 15 oz without any rails on it. That's even heavier than most aluminum rail systems! Compare that for example to the Carbon Fiber tube of the same length that only weighs 4.4 oz.

The Troy TRX extreme are the lightest aluminum rails I've seen, and something to consider, but still seem about twice as heavy as the carbon fiber tubes (with the exception of PRI, which have ridiculously heavy CF tubes for some reason).
7.6" = 7.52 oz
11" = 9.93 oz
13" = 11.43 oz

I understand fully the weight differences, but there's a reason people use them for 3 gun more often than almost any other handguard. These and PRI are used more than just about anything else. They flat work! They do everything well, good grip, great ergos, and in the long run, aren't that heavy. If thats too many ounces, its time to start lifting some weights :D

Stone
05-22-2011, 9:38 AM
I understand fully the weight differences, but there's a reason people use them for 3 gun more often than almost any other handguard. These and PRI are used more than just about anything else. They flat work! They do everything well, good grip, great ergos, and in the long run, aren't that heavy. If thats too many ounces, its time to start lifting some weights :D

I already have an accurate and heavy 9 lb AR15. I'm now trying to build an AR10 and I want to see how light I can get it. I'm hoping about 5.5 lbs total.

The PRI tube just baffles me. The whole point of carbon fiber is to be light weight, yet it's heavier than most of the aluminum tubes I'm looking at. Heck, it's actually lighter to sport a mega arms monolithic upper quad rail system!

bombadillo
05-22-2011, 9:43 AM
Wow man, 5.5lbs is nada for a gun. Pencil barrel with target crown, no muzzle brake, Carbon tube with Magpul MBUS sights front and rear. Standard pistol grip, and ACE ARUL stock is the lightest functional gun I can think of. Maybe a Plum Crazy lower also even though I am not a huge fan. I'd bet you'd be in the 5.5lb mark with those things listed.

Sorry, my reading comprehension sucked. I thought you were going for functional and more on the looks end but realize you wanted the weight reduction. That'll be an interesting one so post up pics or shoot me a pic via PM when done, I'd like to see what you come up with.

thrillhouse700
05-22-2011, 9:44 AM
check out "deadon's" 308 its pretty sick