5.8 pounds as pictured. WWSD style build with a 3 prong FH for a little Stoner nod.

ETA: parts list - faxon pencil, Jag composites handguard, 2A titanium GB, Aero slick side, brownells chrome BCG (will probably swap with a young’s/KE HMB eventually), Geissele CH, Reptilia 1/3 mount with Primary Arms micro, Arisaka offset mount and body with the Malkoff head, surefire tape switch, KE SLT trigger, and JP captured buffer. Sling is the old Frank Proctor slings that I believe are discontinued.

Dude, that is bad ass. Seriously impressive build. Can you give us some details? Sling? Rail? Optic and mount?

Very nice.  Russell recently noted that newer Lancers may sometimes cause issues in the KP-15, just FYI.  Disappointing, as I was hoping to make Lancers my go to mag.

Throw adjustable gas on there & you can pull the buffer weights out, go to a lightweight carrier, drop some more weight.  Very similar to what I want to build, minus the carbon fiber foreend, I don't have that much coin.

I was thinking that's pretty heavy for that little rig, then I realized that's WITH can.  Impressive.  .300?

Thanks man, parts list added


Thank you. Got it zeroed and ran the lancer, GI, and gen2 and 3 pmags. No issues yet so hope that continues. Fun project and really like the WWSD concept  

WWSD inspired build. KE Arms lower, Faxon 14.5" mid-length pencil barrel, BCM MCMR 10" handguard, Geissele SSA trigger, Blue Force Vickers sling. Empty weight without optics is 2.4 kilograms or 5.3 pounds. With Aimpoint M4 and full 30 rd magazine it weighs 3.2 kg or 7 pounds. Love it!



EDIT: Embedding does not work for some reason, I don't get it

@Humminbird77
https://www.ar15.com/forums/general/Picture_posting_tutorial_and_PICTURE_test_thread/168-638569/?

looks like you figured it out.

CompM4 is literally a tank of a red dot, counter to the rest of your build.

Yeah it weighs about a pound with the QRP mount. Would love to get a Comp M5 or Micro T2 but that's some serious cash, about 1000 euros at the moment.  

The Comp M4 has some redeeming qualities too. It's very easy to get behind in difficult shooting positions, as the window is quite large. The battery lasts for years and years, I've been on the same battery since 2016. When it eventually runs out, AA batteries are everywhere so I never need to worry about that. Plus I like the factory QRP mount, it's simple and reliable, no need to adjust tension with tools like with many other types of mounts.

The new Aimpoint budget Micro would be a good fit on that, I don't remember the name of it .

Good idea, I will have a look at that! It was Duty RDS or something like that.

What I would really really like to have is a 2x20mm Compact ACOG, but they are quite hard to find over here and cost a fortune. Maybe I need to offload a bunch of other stuff to get one.

Until you have 50 posts, 3 Team members have to approve your pics.  Keeps noobs from signing up a troll account & spamming the board w/ dick pics.  (has happened, hence the rule).

I carried that same Aimpoint in Iraq, happily just around the FOB.  It's a brick of an optic.

Yes, BSF 10.25”.  Also learned along the way that SLR is the only .875 adjustable block that will fit under a low profile HG.

Attached File


Another update:
Fostech Mach 2 rail 4.6 oz w/ nut
Brownells LW BCG
Lots of 2A and V7 small parts

Almost lost another pound.

4# 12.4 oz bare to 3# 12.8 oz

Under 4# with RRA lower and slick Aero upper.

Very nice.  You're still using a receiver end plate?  Are you using adjustable gas to drop buffer weight?

2A al endplate and castle nut, SA adjustable gas block. I don’t have to use an end plate as my rear td spring is held in by a 4-40 set screw. The 2A end plate is my sling QD attach point and is only 0.15 oz.

Trigger is still a G2S.

Should get to the range to get it tuned later this week.

I have the 27" pencil bbl w/ so little gas I had to pull all the buffer weights out to get it to run.

I have a spare buffer I’m going to pull the weights out of. I’d like to be able to run it that way… we’ll see. Right now it has a standard carbine buffer and the springco “yellow” reduced power spring.

5lbs 12oz.

Niiice

I just got done building this one a little while ago:

- Slick side upper
- 16" Ballistic Advantage pencil barrel
- 12" Carbon fiber Handguard
- KE lower
- Larue MBT
- AIM BCG
- Burris 3x prism optic

Right at 5 lbs unloaded.

Attached File

Nice OP, have a KP-15 waiting for me to install a featherweight mid gas.

My latest…
Ballistic advantage mid length pencil barrel, titanium flash hider and gas block.
Daytona tactical light weight rail. Hogue grip. Slick side aluminum upper with steel takedown pins.
Rubber city lightweight carrier with adjustable gas key, empty buffer.
New Frontier lower with shockwave blade…I had one laying around. :)
Functions perfectly and soft shooting, shoots about 3 moa with irons.

4 pounds, 12.6 oz.

Updated this build with a Primary Arms 3x SLX micro prism to bring the weight down. Now it is 2.6 kilograms or 5.7 lb with optics and sling. Contrary to the picture, I typically use 20 rnd aluminum magazines with this gun. They weigh a little over 0.3 kilograms fully loaded, so the total weight is just short of 3 kilos or about 6.5 pounds.




EDIT: Again trouble embedding, sorry

How much weight are you saving using KE Polymer Lower vs say a Milspec Lower with an A1 Stock?

The KE lower with all parts and carbine buffer weighs 795 grams. Unfortunately I don't have an A1 lower with fixed stock, so can't give a definitive answer, but I have a milspec lower with LMT SOPMOD stock and that weighs 1055 grams. So 260 grams of difference, about 9 ounces.

I think the KP-15 is a little heavier than the Cav Arms Mk 2, but haven't weighed two side by side.

Wraithworks WARP15 is using their variance marked KP-15 lower and their monolithic polymer upper w/ a pencil bbl to hit 5.05 lbs claimed in a $700 factory rifle.  I thought that was a helluva deal for a factory sub-6.

I would guess so too, the KP-15 is a re-design after all, and has thicker cross-sections in some key areas where the Cav Arms lowers supposedly are the weakest. It is also glass-filled polymer and that adds weight.



5 lb complete rifle is impressive especially for that price. If I strip the optics and sling from mine it is very close to the 5 lb mark as well.

Interesting, a polymer upper you say? I tried searching on google but came up with nothing. Anyway, knowing how absurdly cheap injection molding is compared to forged and machined aluminum, someone was bound to do it. The main challenge must be the barrel mounting, they probably need some sort of aluminum insert for the barrel nut and barrel extension, and some hard guide surfaces for the bolt carrier. I wouldn't be surprised if KE Arms takes up this challenge at some point as well.

Looks like they've got some sort of screwed in bbl trunnion, and you could cut a bit off the front of the handguard to shave a little more weight, as well as perhaps use lighter screws, but not much weight savings there.  I presume for that price they're using a full mass buffer & carrier, so add an adjustable gas block, JP carrier & no mass buffer, you might get down to around 4 lbs for just over $1k.  14.5" or 13.7" P&W even lighter, but would likely have to run mid-gas for the aluminum JP carrier.

I used one of the poly/steel uppers for my sinister's .22 LR, just milled an ejection port behind the steel insert on the left side & used the Stag Arms .22 LR insert made by CMMG.  The poly/steel hybrid uppers weren't really any lighter than the aluminum ones, according to what I was told.

I have a 14.5" pencil barrel with mid-gas on mine. I'm pretty sure I could make it run with the parts you mentioned and lose even more weight. However, one principle I try to follow is that uppers and lowers need to be interchangeable between my rifles. Mainly because of local availability issues and some legal restrictions, it isn't that simple to replace things if something breaks. So I guess this is as light as I'm going to make it, at least for now.

A polymer upper is an interesting idea. It works on the G36 so why not an AR-15. G36 has a steel trunnion, but for any real weight saving on the AR-15 I would think it needs to be a hybrid between polymer and aluminum, and even then the weight saving might be rather small as there is not that much material there to begin with. How stable it would be for mounting optics is another interesting question. I believe even the G36 has an aluminum rail on top for optics. So if you end up with an aluminum trunnion, aluminum guides for the bolt carrier, and an aluminum optics rail, the weight saving might not be worth the effort of wrapping it in a polymer housing.

Holy crap I haven’t been on the forum in forever and this thread is still kicking! Glad to see it on the first page. I need to get out and shoot my LW guns, it’s been quite awhile.

6.5lbs as it sits minus can and mag, will be 6 flat once i replace the anchor of a optic thats on it with a 3x microprism.


geo visualizer

KP15 lower
Aero enhanced slick side upper
Faxon 14.5 pencil w/ griffin p/w taper mount
Aero enhanced 15” handguard
PA 3x
random standard bcg/spring/buffer

anyone know if resurgent arms still exists? they had one of the few CF handguards that would work with an enhanced upper.

ill be pretty happy @ 6lbs with no corners cut to shave weight.

Don't think so, they still have a site, but all their handguards are out of stock and they have pulled the listing for the enhanced upper compatible handguards too. Didn't even know that cause I signed up for in stock notifications on one of those, explains why they haven't contacted in a long while.

last social media posts were in november, i messaged them but im not hopeful for a response.

Is that a White Oak Armament 18" stainless steel barrel?

Looks great. Cool to see that setup is in Finland.

Do they have a website. Looked for a complete warp15 yesterday and didn’t come up with anything.

I guess the WWSD concept got a lot of attention, and that might explain the boosted interest in light-weight builds in general. At least for me the WWSD was the spark. I decided to make my own interpretation of the concept since I didn't really want a carbon fiber handguard on my rifle. Call me paranoid, but having broken other carbon fiber sporting equipment in the past, I really don't see a place for it on a carry-anywhere rifle.

I didn't find anything either. If somebody has a link to share it would be greatly appreciated. Always interested to see new developments in the field.

You can get KP-15 lowers in Finland?

Would have thought that they were ITAR restricted.

Brownells Finland has them in stock even right now, also complete WWSD rifles are available with 2-4 business days delivery time. :)  ITAR is a speed bump, it's not a prohibition. When I got my first AR-15 in 2005, there really weren't much available, so I had a complete rifle imported directly from the US by filing for an export license from to the State Department, then finding an FFL that was permitted to do international sales. A big hassle and took a while, but I got it done. Motivation was high, as I follow my grandfather's wisdom of strictly having American made guns and German made cars, but being flexible with women and booze. ;)

No affiliation:  https://wraithworks.com/product/wraithworks-warp15-223-wylde-16-rifle/

Thanks wish they had more details about the upper. Looks like it might be a monolithic design. Could be wrong.

It's almost certainly two halves bolted together with a trunnion in the middle, but might make for a more stable upper than the pure plastic ones we've seen w/ a separate handguard.

I agree, by my count there are 14 smaller screws along the length of the upper, plus 2 larger ones where the barrel trunnion is located. Not quite as elegant as the monolithic lower receiver, but this is probably the simplest way to capture the trunnion inside the upper. The top rail is polymer, not quite sure how stable that will be in the long run. With red dots or other small optics it probably matters very little, and such ultra-light rifles are probably not going to have big scopes mounted anyway.

Has anyone here tried the Kaiser KSP Polymer uppers? Listed at 4.6oz, feels like they would go well with KP15 polymer lower vibe + CF handguard vibe:



https://kaiserus.com/shop/ar-15/upper-parts/upper-receivers/x-7-blackbird-lightweight-ti-graphite-composite-ar-15-upper-receiver/

I had forgotten about them for awhile, but KSP polymer upper and lowes were used by Robar in their 'PolyMar 15' project, which were considered to be good kit.

https://www.americanrifleman.org/content/tested-robar-polymar-15ti/

https://sportingclassicsdaily.com/the-ultimate-msr/

https://gunblast.com/Robar-PolymAR15.htm

I had the older non-Titanium parts version of the KSP X7 receiver and had no issues with it. If I was gonna build another AR, I'd probably snag another one as they were pretty nice and didn't get nearly as hot as Aluminum while out shooting.
Plus, the guy I sold that rifle too has put probably 1,000 rounds through it since he bought it and he still loves it.

One of those on my KP-15 lower, a Smoke Composites handguard, and a pencil barrel would probably be my goal as a backup rifle to my AUG.

Awesome, thank you.

Its funny, I'm an AUG guy as well, and my very rifle plan had been the KP15+ KSP Polymer upper + Smoke composite HG.

Great minds think alike, huh?

18 Inch Faxon Gunner - this is my main/personal favorite AR.   This gun has been through a number of incarnations (several of them I've posted earlier in this thread, and some a fair bit lighter than this one), but I think as of this time I have totally outdone myself and I don't forsee any big changes in the future (HAH! I've thought  that every single time I've majorly rebuilt this gun... give me 6 months).  

As pictured, it comes in at 5.88 lbs unloaded weight, and I must say, that this is the most superbly balanced AR15 I've ever handle.   I'm also happy to note, that there are really zero compromises made in terms of durability or reliability to reach that weight (ie: no milled out/weakened receivers, no poly or magnesium upper or lower, no aluminum castle nuts or end plates, no poly/carbon handguard, none of that kind of thing).   The one thing that some might consider a compromise for weight, is that I did use a lightweight BCG, which used to make me not trust this as much as a mil-spec BCG gun.   However, I have a couple thousand rounds through this setup now, with 0 failures/issues, and I'd 100% trust this gun setup like this to defend my life with it.    I think the shortened dwell time with a 18 inch barrel with rifle gas, and the lower pressure operation of the rifle gas itself come together to alleviate the finnickyness/tuning issues I've had with lightweight BCG's in carbine or mid-gas guns.   With the gas-system adjusted as I have it currently, 223/weak ammo ejects to 4:30-ish and it 100% locks back on an empty mag, and 5.56/hot ammo ejects to about 2:30 and likewise locks back on an empty mag.    Even the hot stuff shoots remarkably smooth, especially given the light weight of this gun.    If I put a comp on it, I bet it would be ridiculously smooth (but I hate comp's, so not happening).

Anyway, on too the specs/parts list:

Aero Texas edition upper (this one is 6.8oz - not sure how/why this one is significantly lighter than all my other Aero uppers, but it is)
Aero S-One 12.7 handgaurd
Faxon Match 223Wylde 18 inch Gunner (markedly more accurate than any of my non-match Faxons have ever been; I've been super pleased with it)
Faxon super-slim 3 prong flash hider (I tested this at night against an A2, and I was shocked to find this out-did the A2 for flash suppression)
VLTOR Mod 4 charging handle
V7 ultra-light forward assist (.3oz vs .8 for mil-spec)
Strike Industries poly port door (.4 oz vs .75 for mil-spec)
Superlative Arms adjustable gas block (1.386 oz says my reloading scale)  (edit to add: I am likely to swap this for a Wojtek adjustable gas block in the future).
Brownells lightweight BCG (8.14oz on my scale - OEM'd by Toolcraft, full auto + serrated for forward-assist use)

Lower: nothing particularly ultra-light on this part - comes in just a whisker shy of 2lbs by itself.
Aero Texas edition M4E1 lower
Larue MBT-2s
CMMG LPK
Aero Enhanced buffer tube
Magpul grip
Mil-Spec-ish stock with QD point (remarkably light at 5.8oz with the sling swivel removed)
Standard buffer/spring setup

Optics
Burris RT-3 (3x prisim scope).   I like this scope a lot more than I thought I would, so much so I wish I had bought a couple more back when PSA had them on for $189.  

Comes in at 5.88lbs unloaded, and did I mention it is superbly balanced?   It is superbly balanced!!!

got mine to 4.84 lbs with suppressor and red dot... but failed to take a complete pic before modding it more

https://www.ammoland.com/2019/05/how-to-build-an-ultralight-ar-15/

EDIT final version was 4lbs 3.6oz, with suppressor and red dot, couple 3d printed parts which lasted the thirty rounds I tested with, then switched back to titanium/plastic etc