I was thinking with the pencil/LT WT barrels now being popular on 14.5 - 16" guns that a LT WT barrel in an SBR length would have even less whip and suppressor droop given that the shorter barrel would be inherently more stiff than the 14.5-16 barrels. Does this seem reasonable? If so, how come we do not see any SBR’s sporting LT WT barrels? It just seems like the LT WT/Pencil thin barrels would really shine in an SBR even more than in a standard (common) length AR.
Isn’t Colt’s 11.5" offering a lightweight profile?
BCM 11.5" Light Weight Barrel Profile: http://www.bravocompanyusa.com/BCM-Standard-11-5-LIGHT-WEIGHT-Upper-Receiver-p/bcm-urg-car-11lw.htm
The Colt 6933 11.5" profile looks identical to that BCM.
EDIT - I take that back, I didn’t notice the subtle difference just behind the FSB. The Colt has the usual “dogbone” shape between the barrel nut and FSB, while that BCM has been profiled down straight in that short section. Can’t imagine there’s much of a weight difference, though.
I wouldn’t tinker with the pencil barrel unless you are running a really lightweight suppressor.
Anyone with significant experience with one?
Do the groups noticeably open up when its hot ?
Suppressor use?
I built mine using a 11.5" LW barrel from Daniel Defense. Its profiled like the Colt 6933 under the handguard. I used the LW to give the gun a balance point at the center of the mag well as configured. I never really shoot this one from the bench, as I have others for that, but I’ve not noticed any wild groups when it gets hot. maybe thats because I suck anyway and can’t tell the difference? I don’t have a supressor, so I can’t help you there.
Every time a LW barrel comes off a lathe… a puppy dies. 
Just doing my part to help control the pet population 
I have a N4 10.5 w/SB & with a M4-2000 it gets really front heavy (as far as balance) and was thinking of ways to cut weight on the front end or worst case scenario put a UBR on it. Just playing with ideas here
Thanks for the replies.
I’ve got a 11.5’’ LW and it’s been great… just throw a rail system on there and you’ll get all your weight back that you were missing
It’s funny and sad that you will get two different answers if you ask about LW or M4/GOV…
Quick answer is that LW is fine.
Exactly how much of a weight difference is there between the LW profile 11.5" and a “standard” 11.5" like the Colt? I seriously doubt it’s more than a couple ounces. The M42K is near 20 ounces IIRC, and way out past any barrel mass, which magnifies the effect of the suppressor even more. I get the feeling the LW profile isn’t going to be a significant gain in that equation.
You don’t/won’t. There’s some documentation floating around that tested pencil barrel weights on colts along with their accuracy under sustained fire. I can’t find it but be on the lookout as it has all of the answers you could possibly want.
It isn’t much - you are correct on that. It is a noticeable amount of difference on a 14.5’’ as I have owned a govt profiled 14.5’’ and then a lightweight profiled 14.5’'…(you can feel the difference by just picking it up)
I haven’t looked back from picking up the LW version and I love it. People tend not to really acknowledge the benefits of the weight savings between LW and Govt profile if they are just taking their rifles to the range and shooting a little here and there… If you take a 2 carbine class you’re going to notice that extra weight as the day progresses…
Why do you hate LW barrels? Standard GI contour barrels are only heavier from the handguard cap to the muzzle. M16 and M16A1’s used a LW type contour. The A2 barrel contour was the result of USMC PMI’s wishing to make the weapon muzzle heavy. it did little to make the barrel more rigid. With all the accessories people add to their weapons, any place one can cut weight without sacrificing reliability, durability or accuracy is OK with me.
Thanks Todd! When I buy new rifles it will always be from Noveske, but I have the build bug now and am enjoying building ARs as I learn more and more each time I do and the ability to play AR God and design a rifle is fun too;)
My weight issue really isn’t with the rifle it is with the can, but I can’t cut a third off the can:p so I was thinking about building a superlight SBR 11.5 and it just seemed like the LW barrel in such a short length would/might have the stiffness to negate any of the negatives of a LW barrel wearing a can (AAC M4-2000). Just playing Dr. Franken-God right now.
Todd do you have a preference between 10.5, 11.5 and 12.5 for 556s? I have your 10.5 Light Shorty w/SB (which I won’t be able to put thru its paces for awhile), but was thinking of building a franken 11.5 and then getting one or your 12.5 GPR rifles at some time. I keep thinking that once I get a 12.5 I’m gonna want to dump all the others. Favorite SBR for you?
I know I won’t get an answer right now since I don’t think the tooling is even finalized, but any idea when the VLTOR VIS-KM will roll out of your house?
I like the 10.5" for mainly suppressed with the shorter OAL, and the 12.5" as a more general purpose carbine. I’ve skipped over the 11.5" and never had much interest in one, heavy buffers and O-ring or HD extractor springs have made the 10.5" just as reliable in my opinion.
I don’t hate them. I just have no use. One of my SBRs it a Colt commando light weight barrel. I keep it because it runs so well.
Other than for Patrol Rifle where you might deploy on a barricade scenario for hours and never take a shot… light weight doesn’t fill a roll for me.
I’m biased towards having more than I need and over-engineering.
I’ve always figured that a SOCOM profile barrel, and VLTOR MUR would have the least amount of POI shift. Especially with a SureFire or KAC can.