View Full Version : Functional Featherweight
My goal with this build was to get something as light as possible, without sacrificing function or otherwise resorting to what I would consider a significant compromise. I know that I could trim more weight off of this build if weight was my only goal, but it wasn't. That means I still went with a RDS and a white light.
Parts:
LMT complete lower
BCM middy upper
BCM BCG
Noveske QD socket end plate
DD Omega
Magpul MOE stock, grip, and trigger guard
Magpul MBUS front and rear
Magpul XTM panels
Aimpoint T1 on Larue
Phantom FH
VLTOR scout light mount with the plastic shim from a VTAC light mount
Nitecore EX10 light
The Nitecore was one of my secrets for shaving weight: it's only 1.2 ounces without a battery but it pumps out 130 lumens. I've carried the AA version (D10) for over a year now every day (since it came out) and am satisfied that one of these lights can handle whatever I throw at it. I like the fact that the switch is a piston system: I don't have to worry about a tailcap going tits up on me.
The major way I shaved weight, however, was that I took this BCM middy upper to Robb at VA Arms Co and had him re-profile the bbl down to 0.625" as well as cut the length and permanently install the Phantom for total non-NFA length. Also, when I told him that I was cutting weight, he suggested shaving the FSB down to a low-pro style gas block. I said, "go for it" and am quite pleased with what he made for me.
Total unloaded weight of this 16" middy is approximately 6.7 lbs. Like I said, I could shave more weight if I ditched the optic/light, or if I used ladders instead of panels, or if I used a crappier stock. I didn't want to do any of these things however. It is plenty light as it is. While standard hand guards would have saved me a few ounces (although then I'd have the weight of the FSB back) my personal preference was for a free-float option with a bbl this skinny.
Oh, and once it was all put together, I just had to hit it with Krylon. It's not a great job, but I'm pleased enough with how it came out. I wonder how many ounces I could have saved if I had avoided the paint :p
http://www.byrong.com/fw/fresh.jpg
http://www.byrong.com/fw/complete.jpg
http://www.byrong.com/fw/light.jpg
nice build (and great work as always gotm4)!
SeriousStudent
08-07-09, 20:14
Very interesting carbine. I am in the process of building a very lightweight, easy to handle carbine. My plan is much like yours.
(Grant, where are those Colt pencil barrels?? ;) )
I've debated doing the exact same thing with a BCM middy barrel.
It looks great - I have been the beneficiary of Robb's work as well, and have been highly pleased every time. You can't go wrong with anything he does.
Thanks for the suggestion on the Nitecore light. I used a GG&G light mount on a set of Cav Arms tapered handguards, and it worked well with a X300. I'll pick up a Nitecore for eval.
What colors did you use for that paint job?
Custom stencils I'm guessing?
BushmasterFanBoy
08-08-09, 00:45
Any reason to go with the DD Omega as opposed to the DD Lite Rail system? (I don't know which is heavier, just curious, as I've always heard a bare-bonesed DD Lite is the same as regular handguards. ) :confused:
What colors did you use for that paint job?
Custom stencils I'm guessing?
I used Krylon's camo line: their dark OD green, brown, and khaki (forget the exact names they use). I also threw in a can of Krylon fusion in a very light off-whitish khaki for those light spots, and an Outdoor Krylon can of a more lime green shade. I'll dig out the cans tomorrow or the next day to give you the exact colors. The fusion gave me the biggest trouble: it didn't seem to like sticking onto the other layers of Krylon as well. As a result, it ran more than any of the other cans. Of course, I wasn't very patient, so I'm sure it would be less of an issue for someone using better technique.
As for stencils, I took tips from this thread (https://www.m4carbine.net/showthread.php?t=4665) and just did freehand shapes on manila folders while looking at some multi-cam gear for "inspiration."
Any reason to go with the DD Omega as opposed to the DD Lite Rail system? (I don't know which is heavier, just curious, as I've always heard a bare-bonesed DD Lite is the same as regular handguards. ) :confused:
According to Rob's chart (http://www.tacticalyellowvisor.net/69016/69058.html), the Lite would have saved me 1.23 ounces over my Omega, and would still have been 1.2 ounces heavier than regular handguards (I.E. right in-between). Remember I was working with a middy here: not a carbine length system.
Also, although it probably isn't the biggest deal in the world, I really like the easy-on, easy-off method of attachment for the Omega and the fact that it doesn't require modification or special tools.
So all in all, I didn't care enough about 1.23 ounces to go for something that was harder to install/uninstall.
Very nice!!!:D
That is one well thought out, functional little carbine.
Any chance that FSB shaved down like that made it's way to a scale before it got reinstalled?
I'd like to compare the weight of:
Stock FSB ??
Middy handguards (7.0 oz)
7.0 oz known
-to-
MBUS (1.2 oz)
shaved FSB ??
DD omega (9.4 oz)
10.6 oz known
Also, although it probably isn't the biggest deal in the world, I really like the easy-on, easy-off method of attachment for the Omega and the fact that it doesn't require modification or special tools.
This is especially applicable given your pinned flash suppressor.
matthewdanger
08-08-09, 07:49
That is slick. I have never seen a FSB shaved down that far!
What sling are you going to run?
Total unloaded weight of this 16" middy is approximately 6.7 lbs.
That is pretty amazing. I always weigh with sling in place so this isn't apples:apples, but that puts you 1.2 lbs less than this configuration (http://i134.photobucket.com/albums/q111/rob_s/gun%20stuff/BCM/WEIGHT-OPTIC-X300.jpg).
What is the weight of the EX10 and Vltor mount combined?
Robb Jensen
08-08-09, 08:26
It looks great. You have nice skills with the Krylon! :D
A few other things that can shave off some weight since it's a midlength would be to use a JP LMOS carrier which is 6.25oz or a if you got one for really cheap a Colt non-shrouded 1/2 circle carrier which weighs 8.63oz. Either will work with a CAR 3.0oz buffer just fine on a midlength. An old Fiberite CAR stock would be lighter but I too would prefer the MOE on it and I like an AR to be a little heavier at the butt vs the barrel.
A 5.56mm barrel could be turned down to .550" but I'm a little leary of taking them down the far. I might try .565-.575" on my own 14.5" stainless RRA midlength 1x8 barrel I have in my toolbox taking up space.
A Daniel Defense Aimpoint Micro mount could shave another ounce off the weight of the optic. If you did go do the JP LMOS carrier since it doesn't have forward cocking serrations you could remove the forward assist from your upper and fill it with the delrin plug which DPMS sells.
Robb Jensen
08-08-09, 08:33
Any chance that FSB shaved down like that made it's way to a scale before it got reinstalled?
I'd like to compare the weight of:
Stock FSB ??
Middy handguards (7.0 oz)
7.0 oz known
-to-
MBUS (1.2 oz)
shaved FSB ??
DD omega (9.4 oz)
10.6 oz known
Next time I do one of these Rob I'll weigh what's left of the FSB. It's very light even lighter than a VLTOR low pro gas block. I'm going to cut my already shaved FSB in half like that.
I keep coming back to this thread - I dig the setup! gotm4, would a 9" or 12" Omega fit over that shaved FSB?
Robb Jensen
08-08-09, 10:12
I keep coming back to this thread - I dig the setup! gotm4, would a 9" or 12" Omega fit over that shaved FSB?
I'm not sure if a Omega will fit over it. That one upper I did quite a while ago did was a CMMG 14.7" barrel with a perm. attached A2 comp with a .625" seat at the FSB, I shaved it way down to fit under it. On Byrons barrel I left the gas block seat at .750" so it's likely too big to fit under the very tight Omega or it'll be damn close. The Troy TRX Extreme rail/FF tube would be a good option too.
matthewdanger
08-08-09, 11:03
I keep coming back to this thread to check out that rifle. This is a very slick build.
That is pretty amazing. I always weigh with sling in place so this isn't apples:apples, but that puts you 1.2 lbs less than this configuration (http://i134.photobucket.com/albums/q111/rob_s/gun%20stuff/BCM/WEIGHT-OPTIC-X300.jpg).
Rob is right, that is amazing. The sling and hardware to mount it will add some weight but that will still be one very light but still very functional carbine.
My lightweight build tips the scales at 8 pounds, 3/4 ounce with the sling.
I have a similar build that weighs a bit more at 8 pounds 3/4 ounces with the sling (unloaded).
- Colt 6520 upper rebuilt with flat top and an M16 carrier (replaced the old half circle carrier)
- H2 buffer
- DD Lite 9.5 FSP
- PWS FSC556
- Aimpoint T-1 on LaRue mount
- TangoDown stubby (non-qd)
- Troy folding rear sight
- Standard FSB
- TangoDown rail covers
- MIAD with winter trigger guard front strap
- MOE stock
- BFG VCAS 2 point sling (mounted to the handguards with a one piece ACE loop, and the end plate with a DD QD mount).
- Surefire G2L (with Z48 switch) in a VTAC mount
http://img98.imageshack.us/img98/469/lightweight1up8.jpg
This is an old pic before the FSC556 and TD Stubby were installed.
There are a few places I could save weight like dropping the Z48 switch, getting rid of the TD Stubby vert grip, using a burnsed loop instead of the QD end plate, and getting rid of the rubber butt pad on the MOE stock, but I like the functionality that these things add. Even if I dropped those items, I think I would still be heavier than your build!
The Nitecore was one of my secrets for shaving weight: it's only 1.2 ounces
How that flashlight work for you? Run time?
I'm butting together an SBR and would like to attach a small light weight light to it.
Heavy Metal
08-08-09, 11:41
Speaking as someone who has lost a taper pin, I like the idea of having two. I don't think I would have reduced everything to only one.
Robb Jensen
08-08-09, 12:57
Speaking as someone who has lost a taper pin, I like the idea of having two. I don't think I would have reduced everything to only one.
Red Loc-Tite or Rocksett is your friend....;)
Thanks for the kind words, gents. I got my hands on a much better scale and my earlier figure was only slightly off. The carbine comes in at 6 lbs 12.8 oz, which would be 6.8 lbs rather than 6.7.
http://www.byrong.com/fw/6128-1.jpg
http://www.byrong.com/fw/6128-2.jpg
Any chance that FSB shaved down like that made it's way to a scale before it got reinstalled?
I'd like to compare the weight of...
I'm interested in that comparison as well. I'll eagerly await Robb's findings once he does the next one that he mentioned.
What sling are you going to run?
Right now I have a padded VTAC that I made into a 1 pt sling instead of 2 pt by connecting it back to itself. I like how it works but I'm not necessarily settled yet.
That is pretty amazing. I always weigh with sling in place so this isn't apples:apples, but that puts you 1.2 lbs less than this configuration (http://i134.photobucket.com/albums/q111/rob_s/gun%20stuff/BCM/WEIGHT-OPTIC-X300.jpg).
My reasoning for weighing without the sling is that sling weight is not something my arms really have to bear: that is a weight that my body takes on. I understand that in a role of humping the rifle around, weight is weight, but I look more for weight savings in terms of tired arms.
Still, I've weighed it with the sling attached and it comes out to 7 lbs 3.8 oz
http://www.byrong.com/fw/738-1.jpg
http://www.byrong.com/fw/738-2.jpg
What is the weight of the EX10 and Vltor mount combined?
My scale says 3.4 oz with battery included.
It looks great. You have nice skills with the Krylon! :D
Thanks man, I appreciate that.
A few other things that can shave off some weight since it's a midlength would be to use a JP LMOS carrier which is 6.25oz or a if you got one for really cheap a Colt non-shrouded 1/2 circle carrier which weighs 8.63oz. Either will work with a CAR 3.0oz buffer just fine on a midlength....
If you did go do the JP LMOS carrier since it doesn't have forward cocking serrations you could remove the forward assist from your upper and fill it with the delrin plug which DPMS sells.
Very interesting. And you don't think there would be any remote possibility of reliability issues with the LMOS?
I'll have to consider whether or not I want to retain forward assist functionality. Definitely something for me to think about.
How that flashlight work for you? Run time?
Here's a very thorough review (http://www.candlepowerforums.com/vb/showthread.php?t=202436) (not mine) including numerous runtime plots. Short answer is that the EX10 will give you 1.5 hours of runtime before it hits 50% brightness, and up until then the regulation is very good (I.E. full brightness is retained through almost all of those 90 minutes) as you can see in the runtime plots in that review.
It's a multi-level light which can be dialed down for lower light and more runtime, but only if you are using it in click-on click-off mode. If you are in momentary only mode (which I keep it) then it stays at max brightness.
Speaking as someone who has lost a taper pin, I like the idea of having two. I don't think I would have reduced everything to only one.
I'll keep an eye on it: thanks for the heads up. I'm no expert so I just put my trust in Robb's hands and let him do his work.
What colors did you use for that paint job?
I checked the actual cans for you:
2902 Moss - this was Satin "Outdoor Spaces"
2423 Satin River Rock - this was the light Fusion
4291 Khaki (camo line)
4292 Brown (camo line)
4293 Olive (camo line)
LonghunterCO
08-08-09, 18:31
A few other things that can shave off some weight since it's a midlength would be to use a JP LMOS carrier which is 6.25oz or a if you got one for really cheap a Colt non-shrouded 1/2 circle carrier which weighs 8.63oz. Either will work with a CAR 3.0oz buffer just fine on a midlength.
Great looking build. Hey gotM4- has anyone had any luck with this carrier in a CAR gas system and regular buffer?
Robb Jensen
08-08-09, 20:49
Great looking build. Hey gotM4- has anyone had any luck with this carrier in a CAR gas system and regular buffer?
I've not known anyone to use one with a CAR gas system. I have over 20K trouble free rounds on a full gas midlength (low pro VLTOR gas block) with both 16" and 18" barrels. With a CAR buffer and standard rate spring with a midlength it still shoots really soft because of the less moving mass. I do run Wolff +10% mag springs 'just in case' the mags couldn't keep up with the added bolt velocity. Wolff mag springs fit into Magpul and Lancer mags with no issues.
Bryons lightweight inspired me so that's why I'm doing one too. I have a SBR lower right now without a upper on it. It'll be a 14.5" stainless barrel turned down to .575" (maybe even cut it down to 13.8") with a PWS FSC556 comp, probably a Troy Extreme tube or DD 9" Omega, JP LMOS carrier, probably a chopped carry handle SP1 upper I have which needs refinishing anyway and use a Fiberite stock, MOE grip and triggerguard. I might put one of my Dr. Optic sights on it with Magpul MBUS sights.
Heavy Metal
08-08-09, 20:52
Red Loc-Tite or Rocksett is your friend....;)
It was as it came from Colt. Lost it in the service.
Robb Jensen
08-08-09, 20:58
It was as it came from Colt. Lost it in the service.
If really skeer'd one could thread the hole on the back end of the FSB (where they drill the hole it in for the gas port) and use a set screw Rocksetted in to keep the pin in place and dimple it into the bbl.......just thinkin' out loud.
If you want one of those Colt carriers, I have one I'll send you for free, no strings attached. Shoot me a PM if you'd like it.
My scale says 3.4 oz with battery included.
Thanks, that thing's pretty light.
If you want one of those Colt carriers, I have one I'll send you for free, no strings attached. Shoot me a PM if you'd like it.
I very much appreciate the offer, but it seems that the weight difference between my current carrier and what Robb states for the half-circle is not that much. I'll stick with what is in there for now, and maybe consider the LMOS in the future. That's really nice of you to offer up the Colt though.
Robb Jensen
08-15-09, 13:03
I weighed some stuff:
FSB = 4.9oz
my ultra low pro shaved FSB = 1.6 oz.
cut in 1/2 shaved FSB = 0.7oz
M16 carrier w/key = 9.7oz
JP LMOS carrier w/key = 6.7oz
I forget the actual weights but interesting enough the one A1 handguard ring was 1/2 the weight of an A2 delta ring.
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