I am hooked on the KISS aspect of an SBR and having my form 1 papers in process for a couple of months now I feel the need to define my goals and listen to others feedback. A good friend has shown me the light with his Bravo Company based 11.5, and as such it is a very difficult standard to beat.
So how would you spec out your build if these were the goals?
Whose barrel
Whose handguard
What gas block
etc
Thanks
Lightest kiss?
Rainier/samson evolution 7" rail
Fixed fsb
Any lightweight barrel at your desired length, probably from bcm
Car stock
Daniel defense a1.5 rear sight
Bcm 11.5 lightweight complete upper with fixed fsb
Bcm bcg and gunfighter ch
Centurion c4 carbine cutout rail (11.6oz with barrel nut)
DD A1.5
T1 in larue or adm mount
CTR on LMT RE with noveske endplate
VCAS with sewn in qd’s
x300
The rail has built in qd mounts and will allow mounting of the x300 at 9 or 3, eliminating two mounts.
The noveske endplate adds minimal weight over a standard endplate and recesses the qd into the receiver for strength.
The fixed fsp and dd A1.5 both for strength and simplicity.
The t1 is mounted with a qd so it can be removed if the lenses are obstructed, a dd mount would be roughly and ounce lighter but I think the qd is worth the extra weight.
The vcas with sewn in qd’s eliminates a few pieces of hardware from the sling
The x300 is bombproof, lightweight, and can be mounted directly to the rail without an additional mount.
I don’t know that it is the lightest setup but it is close to the lightest without sacrificing any practicality.
Get an 11.5" upper w/ FSB and Magpul MOE handguards. Add one of Mossie Tactics light mounts and add a Surefire X300.
You don’t need a rail system to do this.
I doubt that there’s that much difference between an 11.5" lightweight and standard profile. There simply isn’t much in front of the gas block.
My stripped Daniel Defense 12.5" CHF non-pencil barrel, for example, weighs 21 ounces. Interestingly enough, a BCM 11.5" BFH weighs 2 grams less on the same scale. (BCM barrels would appear denser? 
)
Don’t get me wrong- I like 14.5" pencil barrels but personally I’d go with a standard profile in an 11.5" CHF. That BCM 11.5" is a laser.
I don’t think you can get any lighter without sacrificing reliability than rob_s did on his build. 5lb 2oz before the aimpoint!
https://sites.google.com/site/tacticalyellowvisor/projects—guns/10-3-ultralight-sbr
I think that is a pretty simple setup but when people combine the words KISS and AR they usually mean a carry handle setup. I’m building a 10.3" AR pistol that I will SBR if I ever get out of Michigan that you might find interesting. it will be within a few OZ of rob_s gun.
Its essentially a 10.3" A1 style upper. You could just substitute a 11.5" .625 GB (aka pencil) barrel.
Slick sided A1 upper from JSE surplus
http://www.jsesurplus.com/militarysurplusa1uppers-seedetailsforspecifics.aspx
I have an extra non “F” front sight block and flash hider from an A1 parts kit I’m not using since I bought a colt barrel with the FSB already on it for that build. I’ll throw that on but you can pick that up from APEX gun parts.
I also have some extra carbine handguards laying around and I’ll pick up a Colt BCG since I like them better 
For the lower I’m tempted to get a NoDak A1 style receiver but I’m going to buy a couple of Palmetto State Armories $50 receivers. so I’ll probably just use that since this IS a pistol build and nothing special
one built like this that Iraqgunz said.
That’s hardly KISS, Watson. 
Colt A3 Upper
Colt 1/2 moon carrier & bolt
DD LWHFCL with pinned low pro
Option: Bravo Co 11.5 LW CL with DD low pro gas block
75/25% Apex hand guard vs Troy Because Apex just mounts stronger but both have a feel I like. Troy if I go FDE color scheme.
Buis: ARMS 40 something, and DD Front
I also have a Spikes T3 buffer, which may loose a weight insert if necessary. I note my own counter intuitive as to the light carrier and the heavy buffer!
The half moon carrier is a bad idea on a carbine or SBR. Not because of the weight, but because of the lack of a firing pin shroud… unless you have one of those half moon with shroud.
Mine is out of the 1st 6724 I owned, and is indeed a shrouded 1/2 Moon. Appreciate that degree of focus, well done!
aside from the aimpoint it simple
maybe its on the side of the lighter wallet KISS side of things :lol:
If you are going to build an SBR then use a proper non-neutered BCG.
Another very light iteration is the TROY Extreme (or VTAC version) rail in 9" with the X300 and front sight mounted there, with a low profile gas block. DD Fixed sights, and overall weight is still around 6# with the light and an aimpoint micro. The old school carbine stocks are great choices, followed by the MOE stock.
My personal SBR is a variation on this theme.
Cool. The shroud is the critical part. Especially on a short carbine gas gun. But that half moon might chew on the buffer face a little more than a 16 carrier.
I learn a little more each day… The above makes “common sense” when you consider the area the considerable force is directed upon. Interesting is the Colt semi carrier with no shroud that came with my 7.62 x39 “Colt Kit.”
On the lower (a Mega) there is already a MOE buttstock, and the fire control group will be a Giessele. I see that Magpul is offering some new collapsible stocks, so I will be pounding the carpet at SHOT in their direction.
Did I Hijack my own thread?
It may or may not be an issue. I’d just watch it for a while.
I like the DD LW CHF barrels with a pinned lowpro gas block in a VTAC flavored Troy Alpha rail.
Jake
Copying this exact setup but with an 11.5" A1-profile barrel in place of the 10.3" I used will give you a carbine that weighs 1.4 oz more.
Colt 11.5" 6933 barrel
Daniel Defense 10.3" “lightweight” barrel
So assuming barrels gain weight linearly:confused: (1.2”/1.4oz=1”/Xoz) than every inch of barrel weight beyond 10.3" is adding 1.16oz of barrel weight. So a 14.5 barrel would weigh 1lb 5.18oz and a otherwise identically setup gun with that 14.5” barrel would weigh 5lbs 6.9oz.
Maybe that new Rainier Arms upper would drop another 2oz?