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View Full Version : Dueling 12.5's - build planning, ersatz-GL/SSC vs GAU-5 ASDW



Diamondback
04-06-20, 16:49
Stick, hope you don't mind me starting this here since you're one of the few experts on the subject.

As some folks will recall, I tend to be a fan of starting my builds based on proven military-issue engineering and then adapting based on my needs, NFA compliance or component availability. Right now I have the PDW role covered by a "Mk 18-ish" build, the C8 and M4 (under construction) have "Service Rifle/Carbine" taken care of, so I'm looking at something in between and the dueling options are various GL/SSC-based setups or a GAU-5 ASDW. Mainly we're discussing URG's here, the bottom halves will all be the same either way going together as a pistol--the questions there will be whether to go clone or improve via the A5 system, and whether or not to add a LAW sidefolder. (Primary mission on this build will be Home D, but I also like all my irons to be built close to something mil-issue that I can use for class Range Days when/if I break back into academia so it needs to be something that can pass for its military counterpart in a "shoot this, shoot its generations-past counterpart then write Compare/Contrast paper" role.) Other assumptions are that I don't really need to engage beyond about 200-300 yards, I prefer fixed iron sights and the less moving parts required to make ready to fire other than "flip safety off or charge" the better. (The only reason I use Diamondhead folders is I find them especially suited to my bad eyes--seriously, back in college the guys I shot with used to call me "Gun Tommy, shoots by sense of smell"--and if I could somehow jigger them into fixed or get DH to make me a non-folder adaptation I would in a heartbeat.) Other relevant notes, this build will be neither a grenade launcher nor a suppressor host.

Option 1: Midwest GAU-5
Pros: Off-the-shelf. Breaks in half with quick reassembly should a discreet-carry/transport situation arise. Longer BUIS sight radius.
Cons: Folding sights require deployment on top of assembly before shot. No "issue config" optic. (If I go this route and add an optic, I want it to be one that could hold zero through the knocks of a Martin-Baker Fan Club ejection and landing.)

Option 2: GL/SSC rumored variant, based on Centurion upper with 10.75" KAC URX-II rail
Pros: Components nominally available. Optic friendly. LPVO friendly if optics turn that direction. More rail than RAS.
Cons: Folder front sight requires deployment. Removal of gas block and some outsourcing to currently-closed pro smith for rail install and torquing required. Less rail than Centurion. URX-II getting hard to find and requires special tools.

Option 3: GL/SSC "Block 1," Centurion upper with M4 RAS
Pros: Simple, classic method. RAS is drop-in install I can do at home. Fixed FSB means less moving parts.
Cons: Limited rail space. LPVO pointless with FSB, so useful optics limited to RDS.

Option 4: GL/SSC "Ersatz Block 2" FSP, Centurion upper with C4 Pocket Rail
Pros: Off-the-shelf factory assembled option, when Monty has parts stock. Fixed FSP.
Cons: Requires 0.2" shim behind FH to restore FH/rail clearance geometry or use of a "non-standard" linear comp/blast shield.

Option 5: GL/SSC "Ersatz Block 2" Flattop, Centurion upper with 12" C4 Rail
Pros: Off-the-shelf factory assembled option, when Monty has parts stock. Longer BUIS sight radius.
Cons: Requires 0.2" shim behind FH to restore FH/rail clearance geometry or use of a "non-standard" linear comp/blast shield. Folding BUIS requires deployment.

Based on these possible options and their pros/cons, I'm throwing this out to Stick Nation for opinions... Any of you guys see any advantages/disadvantages each option may have that I've missed, or anything that should move some options up or down on preference relative to others? (Eventually I'd like both a "GL/SSC-ish" and an ASDW in the rack, but as it is the house already has more iron than shooters so we're adequately equipped and the second in same role would be a luxury.) Remember, this has to be an NFA-compliant "Pistol" or "Title 1 Other" build... which means probably no VFG, definitely none if outfitted with a LAW.

JediGuy
04-07-20, 00:21
The GL/SSC is just unique enough to be fascinating to me, plus a 12.5” upper was the first AR item I purchased.

But, I think if you want to be close to the original, you only have Options 1, 2, or 5.
Option 1 is cool in its own right and the easiest. I may get one of these eventually. Or not.
Option 2 is apparently/allegedly close to a version of a GL/SSC, but unnecessarily complicated.
Option 5 would be my selection. Personally, I’d probably go with the Forward Controls Design RHF4 11.5” (custom version of Centurion Arms C4) just to keep life simple.

Diamondback
04-07-20, 22:10
Thanks, JG. The RIS FSP was prototyped and assigned an NSN, I'm just not sure how many of them there were among the 125 SSC RIS's made--it might be a "Unicorn of Unicorns."

JediGuy
04-08-20, 08:20
If you get/have a picture, Id love to see one for those.

Diamondback
04-08-20, 10:47
If you get/have a picture, I’d love to see one for those.

Daniel Defense part number is DD-8050, NSN 1005-01-566-5284 for the rail or 1090-01-D12-0983 for the complete URG. Trying to find the SOPMOD Program PDF I saw the photo in again.

Hammer_Man
04-09-20, 11:32
The C4 rails are very solid, and only require basic tools to install. KAC URX rails are also very solid, but require a special tool to install. If you decide on the URX II, I'd be happy to install it for you, or lend you the tool.

Diamondback
04-09-20, 12:58
Thank you, HM--the URX is a lot of "ifs" at this point, as are all these concepts: *if* the project happens, *if* that option's selected and *if* I can find one. C4's, my plan would be to just have Monty's crew build and ship the entire URG as a complete unit other than shimming the FH.

Big question before even proceeding is if it's Time Zero, and you have a GL/SSC and an ASDW in the ready rack and have to pick one or the other, which one of the "midsize shorties" do you call upon to defend your home and loved ones?

TehLlama
04-10-20, 11:12
The DD GL/SSC has been my white whale for quite a while now... although for any masterkey type applications I'd realistically be trying to do with this, that particular rail isn't all that key.
Once I've let that go, realisticaly I'd want to be on a URX and use most of the length - without any dedicated underbarrel attachments, might as well make it as long as possible.

JediGuy
04-10-20, 11:13
They are both 12.5” barrels with quality components. If you want to keep in “closer to clone” status, I imagine the ASDW wouldn’t come with an optic. In that case, I’d grab the GL/SSC. But, other than that, I think the ASDW brings an additional, unique capability in its ability to be broken down.

Diamondback
04-10-20, 12:54
They are both 12.5” barrels with quality components. If you want to keep in “closer to clone” status, I imagine the ASDW wouldn’t come with an optic. In that case, I’d grab the GL/SSC. But, other than that, I think the ASDW brings an additional, unique capability in its ability to be broken down.

Even though it might not be "clone perfect," if I could find a compact red-dot that would plausibly hold zero through an ejection-seat ride and parachute landing I'd have no qualms racking it on. "Clone Correct" Elcan SU-230 for the SSC seems a bit big and heavy for CQB...

Hammer_Man
04-11-20, 07:33
Right now might not be the best time to shop for a URX II, as the Knight's Armament online store is closed right now due to Covid-19. They were the only place I could find URX IIs in stock when I was toying with idea of another 11.5" build.

IMO, if you're not a fighter pilot making your way on foot through hostile terrain, then a GAU-5 isn't really necessary.

Diamondback
04-11-20, 23:04
Right now might not be the best time to shop for a URX II, as the Knight's Armament online store is closed right now due to Covid-19. They were the only place I could find URX IIs in stock when I was toying with idea of another 11.5" build.

IMO, if you're not a fighter pilot making your way on foot through hostile terrain, then a GAU-5 isn't really necessary.

I don't think I've ever seen the URX-II in stock at KAC in the couple years I've been in the AR game, unsurprising since it's considered "2 generations obsolete". Re the GAU, part of its appeal is that it gives you almost a full M4 that can still discreetly fit into a Bug-Out/Get-Home Bag, alongside the "novelty" factor.

Hammer_Man
04-12-20, 00:50
I don't think I've ever seen the URX-II in stock at KAC in the couple years I've been in the AR game, unsurprising since it's considered "2 generations obsolete". Re the GAU, part of its appeal is that it gives you almost a full M4 that can still discreetly fit into a Bug-Out/Get-Home Bag, alongside the "novelty" factor.

They had them in stock a few months back. I almost ordered one, but I had other financial obligations at the time. I was very tempted though. I remember going as far as putting my CC info into their checkout screen.... You may want to call their office, and see if they have any you can buy over the phone...

I can agree with the novelty factor. If it suits your needs that's great.

Diamondback
04-12-20, 01:20
They had them in stock a few months back. I almost ordered one, but I had other financial obligations at the time. I was very tempted though. I remember going as far as putting my CC info into their checkout screen.... You may want to call their office, and see if they have any you can buy over the phone...

I can agree with the novelty factor. If it suits your needs that's great.

True... "needs" I have a Mk 18 and my trusty old 1911 for Bad Breath Distance and a C8 and soon M4 for "reach", anything more is just adding more options and "improving"--as it is we already have more systems than personnel to operate them. Eventually, I'd like one of each, so at this point the debate is more about prioritizing which is going forward first.

Stickman
04-14-20, 10:21
I need to get a group shot of my various 12.5"s. Here is the current configuration of her as she sits at the moment...

https://66.media.tumblr.com/f769949c3dc1b461d462728812470fe8/8acfe496c9d4c5b7-77/s1280x1920/f612b4b74c992e5cc566fe4b6d7b382edb3049b1.jpg


https://66.media.tumblr.com/e8a98e712f9c768b3806a15241c97d35/f0ffa68fa88f708a-e2/s1280x1920/055d0ed62bb90046857d0df9fcc5c8f86662aea7.jpg


https://66.media.tumblr.com/f326f12485b3af5d1aebfb6f942e7e5a/690f3310fa37d108-bc/s1280x1920/e2bd498bf7d4b0fd910359e31203df0f8a0f6d01.jpg

Stickman
04-14-20, 10:24
The GL/SSC is set up as primarily a daytime weapon, below is my primary night time/ bump in the dark gun in MK18 flavor.

https://66.media.tumblr.com/413387ca3e91186a595a564eff4435ef/254d9eb08474e21f-3f/s1280x1920/758068fc37ec71793b312180ebcf8e64ef4f6bf7.jpg

https://66.media.tumblr.com/6f01379ddc6dd5a6682cec2dc7f784a8/611ad64af029d571-ae/s1280x1920/edbb68487a2719e74f9ca177e9c2181edde4b50e.jpg

JediGuy
04-14-20, 11:38
Honestly, Stick, with options at 10.3/11.5/12.5 with good ammo, for practical purposes, do you see much point in anything longer than a 12.5 besides maybe an 18 SPR?

Diamondback
04-14-20, 18:06
The GL/SSC is set up as primarily a daytime weapon, below is my primary night time/ bump in the dark gun in MK18 flavor.

Ironic that the roles are reversed for our purposes... my Mk 18, once reconstituted onto a live lower, is on day shift because it can be more discreetly carried while anything bigger leaves rack only for Range or Bump-In-The-Night.

61763
This pic doesn't have the laser, tape, blast shield or left-side and brace-mount spare mags, but see anything you'd do differently or might be an NFA issue if this goes onto Live Iron? (Ready-to-fire length is 25.925 from A5 tube through to muzzle crown, though I'm not sure how the "unsafe to fire folded" LAW compares to irons that are meant to fire while folded. You know ATF, not happy if the rules are predictable...)

Stickman
04-21-20, 16:01
Honestly, Stick, with options at 10.3/11.5/12.5 with good ammo, for practical purposes, do you see much point in anything longer than a 12.5” besides maybe an 18” SPR?

Sorry that I missed this question. I think once we start to reply with yes or no, we get back to condensing that idea that we may as well all use 12.5s. It also brings up the question of ammo and by that point we are on the slippery slope to all arguing that "Stick sucks, we should just carry Mk18s".

JediGuy
04-21-20, 20:21
"Stick sucks, we should just carry Mk18s".

That would be interesting, since I believe you shared pictures of your go-to 10.3” carbine. I guess haters gonna hate.

Hammer_Man
04-24-20, 20:18
https://www.operationparts.com/kac-knights-armament-mid-length-urx-10-3-4-sr15-ar15-includes-built-in-front-flip-up-sight/

FYI URX II in stock at Operation Parts

Diamondback
09-14-22, 21:35
Dusting off and updating now that Midwest has discontinued the G3ML10.5 rail and complete ASDW uppers...

ComponentCommonVendor/CostASDW SpecificVendor/CostGL/SSC SpecificVendor/Cost

Lower Receiver
Aero M4 clone
my usual FFL






Backend Kit (buffer, tube, spring)
std-length pistol tube







LPK
Damage Industries







Ambi Safety
Schmid
Arms Unlimited 15






Ambi mag catch
Norgon clone
Arms Unlimited 25






Grip
(build specific)

FAB AGF-43 folder, black
Lanbo's 39.33
FAB AG43, FDE



Upper receiver
Aero AR15 assembled
Lanbo's 74.26






Barrel, Gas Block, Gas Tube, BCG
Rosco Bloodline 12.5" Sauce Kit
Lanbo's 249.30






Takedown Kit
(ASDW only)



Cry Havoc QRB 2-pin
Brownells 425 OR
OpticsPlanet 409.99
(whoever has better coupons at Go Time)


Handguard
(build specific)

Midwest 10.5", either:
G4M10.5 OR
CRM10.5
Lanbo's 139.36 (G4)
OpticsPlanet 122.37 (CR)




Charging Handle
Basic milspec







Muzzle Device
Spares-bin A2







Iron Sights
(build specific)

Magpul MBUS PRO
Lanbo's 129.19/set
??? (recheck refs)



Optic


NA

?Elcan SU-230 or SpecterDR 1-4x



Grenade leaf-sight
(GL/SSC only)

NA

???



37mm faux-M203
(GL/SSC only)

NA

???

Diamondback
11-04-22, 20:24
Game On! It's not "pure" in light of the G3 being toast, but I'm using a Combat Rail Lightweight and planning MBUS 3 sights calling it "ASDW-PIP" for "Product Improvement Program." I'm gonna have the anti-rotate tabs chopped, since I figure the Air Force gunsmithing shop wouldn't particularly care about commercial warranties. Dvor got the QRB for $370, so that was like a sign from above that it was Go Time.

https://cdn.discordapp.com/attachments/655632728812683276/1038245150956204072/20221103_205611.jpg

Left to do: the folding grip, lower receiver (I need to call my FFL and see if they still have Aero faux-M4's), barrel/gas block and BCG (all in the Rosco Sauce Pack).

JediGuy
11-05-22, 06:33
Should be cool once its together. And even if the local FFL doesnt have the lower you want, prices are down everywhere and its Sale Season..,

Diamondback
11-05-22, 10:01
One other PIP item: While current ASDW has its parts "float" separately in the bag, the PIP version will use a QD riser and double-sided Picatinny claw adapter to make the two sections a single piece in the bag.

Disciple
11-05-22, 11:52
One other PIP item: While current ASDW has its parts "float" separately in the bag, the PIP version will use a QD riser and double-sided Picatinny claw adapter to make the two sections a single piece in the bag.

Is that what the lower rail section you added is for?

Diamondback
11-05-22, 12:06
Is that what the lower rail section you added is for?

Plan is to use the rear top-rail stub for "stowed" connection. The lower rail is in case either the connector blocks the sights and I need to make it fully removable, or the Cry Havoc crud-cover blocks the stub and I need a different mount point. As of about five minutes ago, I'm now thinking move the connector-stowage up front so it can pull double duty as a handstop... maybe depending on space and clearances rack in a mag-carrier along the top or bottom.

Side not here, a lot of this depends on the height of the folded MBUS 3's--if they're low enough to "close couple" and the riser-coupler combo low enough to not block sight picture, the coupler just stays mounted on the upper receiver. If it needs enough extra clearance that I need to add a second riser, then the "remove and remount" scenario comes into play. Funny: I never thought I'd have anything good to say about Leapers UTG, but I think between this and the modular backends on my "Quick-Change Charger" I may have found a niche where they actually ARE good for something!

Another note: The concept on ASDW-PIP calls for a ten-round flush-fit mag (eg, 10-rd PMAG) in the well and ready to go at all times except when legally prohibited, in addition to the USAF standard 4x30 in two (not USAF spec) double-mag pouches. Yes, this makes PIP a bit heavier than its root design, but I'm still trying to keep it lean, clean and agile rather than "Gearqueer Visit from the Gadgets Fairy."

Disciple
11-05-22, 12:42
Modular backends?

Would a 15-round magazine (https://www.larue.com/products/e-lander-5-56-15-round-magazine/) be about the same height as the folded grip?

Diamondback
11-05-22, 13:06
Modular backends?

Would a 15-round magazine (https://www.larue.com/products/e-lander-5-56-15-round-magazine/) be about the same height as the folded grip?

"QC" was meant to exploit the same pistol-to-rifle-and-back capacity of a T/C Contender or AR pistol, using the rear brace-mount rail of the Charger Takedown and interchangeable barrels. (Leapers 3-slot QD riser, Midwest sidefold storage tube with SBA3 or SOPMOD slid on--right now the SBA3 is in my storage unit and I keep a railcover on the back unless the 16" barrel is on. Concept was "if I were building a briefcase gun for 007 like From Russia With Love"...)

A 15 would stick out a good bit more I think, the FAB folder really doesn't project very far--maybe 1/4 to 1/3 inch from the bottom of the lower. Would be worth experimenting if WA hadn't just gone Klinton Klip Bullshit, though.

Diamondback
11-07-22, 09:39
Further PIP revision: Cannibalized the Vltor A5 pistol backend and PWS ratchet endplate/castle nut off the "Mk 18 Mod Briefcase" mockup, along with its ODG folding grip in place of USAF black. (Grip and PWS plate/nut aren't PIP, it's a combination of "use parts already on-hand" and ODG kind of becoming a "signature" on my non-clone builds since I'm all about bottom-feeding with sales, discounts and clearance. (C. tells me I out-powershop many women she knows... I'm still not sure how to take that.)

Diamondback
11-09-22, 19:29
PIP component-coupler installed as a test fit:
https://cdn.discordapp.com/attachments/655632728812683276/1040059175511805982/20221109_162234.jpg

A3 Tactical double-ended Pic coupler with 3-slot Leapers UTG riser. Crossbolt is in the foremost slot of the rail stub due to length of the Cry Havoc protective cover.

Diamondback
11-22-22, 22:12
Further update: A5 added too much length for intended case. MBUS 3 sights arrived today, work very nicely with this coupler neither mechanically blocking the join nor optically blocking the line-of-sight. Dowel rods and rubber bands are temporary "alignment jig" until I get the barrel ordered.

https://cdn.discordapp.com/attachments/655632728812683276/1044742169900109834/20221122_143100.jpg

https://cdn.discordapp.com/attachments/655632728812683276/1044742768154656778/20221122_143309.jpg

https://cdn.discordapp.com/attachments/655632728812683276/1044810151892373545/20221122_143527.jpg

Disciple
11-23-22, 12:20
What is the assembled length of the unbarreled upper mounted on a carbine-extension lower?

Diamondback
11-23-22, 16:09
What is the assembled length of the unbarreled upper mounted on a carbine-extension lower?

Didn't have a lower handy to test, will get back to you. Also in the middle of a property manager-demanded cleaning binge, pop a flare if I don't have an answer by Monday AM. :)

Diamondback
11-23-22, 22:16
15-1/4" in Stowed, 27" Deployed. Basically a standard 12.5" AR with a 10.5" rail other than the Cry Havoc QRB adding another inch. Bear in mind the "minus barrel" upper will be around 1/8 to 3/16" shorter once I get the tabs lopped off to properly mount the rail...

Prefatory note before I post the photos: This lower was first completed as a pistol, and in these photos it has neither barrel nor BCG attached. If you look close in the ejection port you can see the hammer forward as an additional safety measure. There is no NFA violation here because this is not a complete firearm; once the barrel arrives it goes straight to my storage unit still sealed in package until its own pistol lower is ready for it.

https://cdn.discordapp.com/attachments/655632728812683276/1045172365765652480/20221123_185801.jpg
https://cdn.discordapp.com/attachments/655632728812683276/1045172565175447633/20221123_185915.jpg

Disciple
11-24-22, 15:40
15-1/4" in Stowed, 27" Deployed. Basically a standard 12.5" AR with a 10.5" rail other than the Cry Havoc QRB adding another inch. Bear in mind the "minus barrel" upper will be around 1/8 to 3/16" shorter once I get the tabs lopped off to properly mount the rail...

Thank you for the measurement. Pardon me, I realize the length is almost the same as a regular unbarreled upper receiver which I should have measured myself. I don't know why I was under the impression this unit added any significant length.

I understand the desire to copy the GAU-5 and have a minimum length, but with that measurement I find appeal in the idea of a pin&weld barrel. That would be about 16+3/4" on the fore half and allow the use of a stock. Most stocks cover the end of the tube and add a little length. Even the SBA3 brace adds something however small.

Happy Thanksgiving.

Diamondback
11-24-22, 18:02
Happy Turkey Day to you and yours as well!

Actually if I read it right, the QRB adds next to nothing to OAL, just kicks the handguard an inch and a half forward around the barrel. https://cryhavoctac.com/about.html "Min compliance" length would be around a pin-weld 14.7" with A2, but I'm not sure if it would fit in this case and then you get into the can o' worms about "rifle and loaded mags together in vehicle" in states like WA where Fish & Game think "only a poacher would have any reason for loaded gun in car." Keeping it pistol means it's covered by a carry permit, and potentially dodges FOPA requirements in states with reciprocity.
https://cdn.discordapp.com/attachments/655632728812683276/1045449883861123152/20221124_131559.jpg

In WA, the standard for "pistol" is "less than 16" and fires with one hand--if you can conceal one of those 10" Tommy Gun pistols with no VFG, you can legally carry it on your CPL here. Not a good idea and prosecutors jack off to fantasies of assraping a CCW Defensive Shooting case with so blatantly "un-sympathetic" an iron, but you CAN do it. This thing is meant almost purely as a Range Toy and maybe occasional "hotel-room defense" duty when traveling, but generally not a Serious Work iron even though I'm building to my normal "would I let my loved ones bet their lives on this in an emergency" standard.

Another question as part of the "Product Improvement Program" concept, right now I'm starting to wonder if there's something already in the military supply system that offers better performance than the A2 FH in a similar space-footprint...

Diamondback
12-02-22, 22:17
Now that the case and mag pouches are in...


Boring messenger bag/manpurse, right?
https://cdn.discordapp.com/attachments/655632728812683276/1048349960543928321/20221202_132059.jpg


SURPRISE!
https://cdn.discordapp.com/attachments/655632728812683276/1048350432403148840/20221202_132206.jpg


But wait, there's more!
https://cdn.discordapp.com/attachments/655632728812683276/1048350921157001316/20221202_132244.jpg
Plan is four mags in pouches and a sling down here, subject to revision as needed--I need to borrow four GI mags from C.'s case for test fitting.


EDIT: Four 30rd GI-type mags with Magpul pulls make a tight squeeze, but without barrel/FH and ammo this case weighs 7.8lb.

Diamondback
12-08-22, 00:20
Update: Two double-mag pouches was No Bueno, but the case is long enough for a half-filled GPS 8-pack in a single layer of four. Properly placed, I think a sling could be easily packed in around the barrel and buffer tube.

Did a little tinkering with some of the scraps of that overweight CASV 10.3, and while it wouldn't be Flight Rated in this config I think the compact light, laser and sling-mount/handstop add significant function at negligible cost.
https://cdn.discordapp.com/attachments/655632728812683276/1050271634751229992/20221207_202624.jpg

https://cdn.discordapp.com/attachments/655632728812683276/1050271752888004678/20221207_202751.jpg

To really work this I need to get another M-Lok rail section for the Lasermax tapeswitch and another QD sling swivel. Test sling is one of the cheapo ones that comes with these Midway bags.

Disciple
12-08-22, 12:15
Coming together nicely. Are you staying with the bare receiver extension?

Diamondback
12-08-22, 12:27
Coming together nicely. Are you staying with the bare receiver extension?

For now, until we get a court ruling that shoves the impending brace-ban back up ATF's craplocker--for "discreet applications" I actually prefer the old fixed SBM4 over the adjustables because it can be turned into an onboard mag carrier with no added space cost, which you can't do with the adjustables because of the track and latch hardware.

Still wish I could find someone to develop a locking hinge coupler that'd work around the QRB with "pull back to unlock/flip/pull back and latch to lock" rather than still having to fut with "manual unlock then manual join"--the game here is to shave seconds off deployment time as much as possible.

Disciple
12-08-22, 13:10
Still wish I could find someone to develop a locking hinge coupler that'd work around the QRB with "pull back to unlock/flip/pull back and latch to lock" rather than still having to fut with "manual unlock then manual join"--the game here is to shave seconds off deployment time as much as possible.

Since the barrel extension needs to enter the receiver in a straight path that seems unlikely without a complicated—and therefore bulky, heavy, expensive, or fragile—mechanism. But please prove me wrong. :)

Diamondback
12-08-22, 13:15
Concept was you pull the entire front-end assembly about an inch toward you to unlock, which then as it flips puts the BE an inch forward, then pull the assembly backward sliding BE into receiver--ideally this would make the QRB latches there "just to make sure."

Disciple
12-08-22, 13:40
-ideally this would make the QRB latches there "just to make sure."

A complete re-engineer the coupling device then?

Diamondback
12-08-22, 14:00
A complete re-engineer the coupling device then?

The QRB itself would be unchanged, just that the current hard-dock "storage only" rail-to-rail coupler would evolve into something more like Vera from Firefly. That's for another day, though, the entire purpose of this one was a quick-and-cheap proof of concept on "join the pieces into one for grab-and-run with minimal impact on deployment time."

Disciple
12-08-22, 14:18
"My days of not taking you seriously are certainly coming to a middle."

Diamondback
12-19-22, 18:24
Barrel has arrived, BCG ripped out to preserve "mechanically incomplete" status. Remaining to-do:
Have pro smith chop alignment tabs
Have pro smith torque and time QRB star nut, HG mount nut and flash hider
Pin gas tube
Source and install CR2016 and 1/3N batteries for light and laser
Source and install M-LOK rail section to mount Lasermax tapeswitch
Find Lasermax zeroing allen-wrench in the crap-pile of my storage unit



https://cdn.discordapp.com/attachments/655632728812683276/1054530200223879258/20221219_143712.jpg
https://cdn.discordapp.com/attachments/655632728812683276/1054529977057542154/20221219_143308.jpg

Sling is a cheap airsoft 2-to-1 off Amazon meant only for "range/inert trials"--were I actually writing up the PIP partslist for USAF Armament Shop I would be recommending something like the BFG Vickers 221 or similar convertible. Lasermax unit is set so it fires through a hole in the Damage Industries slingmount/handstop.

Diamondback
12-24-22, 11:19
Disciple, since you specifically asked about this, based on pre-cut lengths once it's all snugged down and finished the front of the rail should be about 3/16 to 1/4" behind the barrel shoulder on a 12.5".

Disciple
05-03-23, 13:06
Diamondback, any updates?

Also, and pardon me if I asked before, do you know the added weight of the QRB itself?

Diamondback
05-03-23, 16:48
Off the top of my head I don't know added weight, lemme rustle up some tools and get back to ya. Could be a bit.

Updates: While I had WANTED to hold-out the BCG as a token "last step" for while my FFL and gunsmithing mentor watch*, Dickslee forced my hand with the HB1240 ban so I shoved that in along with a Damage Industries pistol tube--the kind that's rounded around the rear edge and has a QD socket so it's "distinctly not shoulderable." It's mechanically ready to test fire, but not ready to zero until I can get D&M to return my calls/emails (they were slammed with the pre-1240 beat-the-ban rush) and see about cutting down the alignment tabs on the handguards. The MI Lightweight Combat Rail right now rests on its barrel nut, it'll protect your hand from the hot barrel but it won't hold alignment to use the sights and whatever you do DON'T apply any forward pressure on it. It's still ready to centerpunch any meth-head that forces his way past my door though...
*This was a standard practice for me, they liked to be "present at the creation" when I put the finishing touches on a build and declared it ready for use. The ASDW and the 007 Briefcase Charger are the only two builds in many years I haven't done that with, due to Exigent Circumstances. Right now other than finishing our M16A4 and C7A2 uppers, further builds are on hold while the "fun fund" replenishes... and then I have to hope that either the courts strike down 1240 or after King Jay the Worst is out I can get a Longslide 1911 I doodled out back in college moving before our Rumored Pederast Attorney General comes back to double down for Round 2.


Pro Tip to all the scumbags out in the world: That heavy metal storm door with the heavy duty locks isn't here to protect me from you. It's here to protect YOU from ME, because once you breach it All Bets Are Off.

Disciple
05-03-23, 17:45
Off the top of my head I don't know added weight, lemme rustle up some tools and get back to ya. Could be a bit.

LOL, no please don't pull it all apart just to weight it. But thanks if that's what you meant.

The DI pistol tube is interesting but 6061 concerns me a little. Maybe not a problem on a pistol. I could see the QD socket stripping out with hard use though.

Diamondback
05-04-23, 19:28
With any luck the DI tube won't be needed for long, it only needs to last long enough for Asshat Terrorist Fascists to get bent over and bitchraped in the courtroom.

I WAS gonna say separating barrel, QRB and upper should be easy since I only hand-tightened the barrel nut... then I remembered the QRB star-nut (shorter barrel-nut) requires a barrel nut wrench and mine's in the storage unit two hours away. :( If I had all my tools over here it'd be five minutes tops combined dis- and re-assembly.

Disciple
05-05-23, 10:09
I have to ask for your indulgence after all: please do weigh the system when you have time & tools. I have looked high and low and I cannot find any measurement of the weight the QRB adds. I almost cannot believe that none of the reviews and promotions mention this; do they make you sign a NDA or something? :rolleyes:

Diamondback
05-05-23, 11:17
I have to ask for your indulgence after all: please do weigh the system when you have time & tools. I have looked high and low and I cannot find any measurement of the weight the QRB adds. I almost cannot believe that none of the reviews and promotions mention this; do they make you sign a NDA or something? :rolleyes:

GAU assembled weighs 6.4lb empty, so just take a 12.5 wafflestock and subtract its weight from that. :)
https://www.tactical-life.com/firearm-news/cry-havoc-gau-5a-takedown-rifle/

Disciple
05-06-23, 20:37
GAU assembled weighs 6.4lb empty, so just take a 12.5 wafflestock and subtract its weight from that. :)
https://www.tactical-life.com/firearm-news/cry-havoc-gau-5a-takedown-rifle/

Honestly not sure if you mean this tongue in cheek or not. Where do I find the weight of the same configuration, handguard, sights, etc., without the QRB?

By the way I found a 7075-T6 pistol tube with QD at the end: https://www.strikeindustries.com/si-ar-carpre-slick.html

Diamondback
05-06-23, 21:01
Honestly not sure if you mean this tongue in cheek or not. Where do I find the weight of the same configuration, handguard, sights, etc., without the QRB?

By the way I found a 7075-T6 pistol tube with QD at the end: https://www.strikeindustries.com/si-ar-carpre-slick.html

Do you have a 12.5" "standard" wafflestock build with MBUS sights? If so, take the handguard off and weigh the rest of it, I'll weigh the MI handguard and then we subtract that total from 6.4. Pretty much any Government-profile 12.5 should do as a stand-in, gas tubes and lo-pro blocks shouldn't differ that much. The MBUS sights weigh almost nothing. (Not being flip, trying to crutch you to an answer because of yet another case of my mother's self-inflicted injuries keeping me stuck closer to home until whatever she pulled or twisted is back to normal. I swear she does this shit on purpose, because it happens like clockwork whenever I start making headway on things...)

As loath as I am to do "tacticool" like SI, that might be worth a look if the DI doesn't hold up or the courts don't go our way. If they do, however, back to CAR tube and SBA3/SBA4... :)

Disciple
05-06-23, 21:23
Do you have a 12.5" "standard" wafflestock build with MBUS sights?

No, I have nothing like that unfortunately. I see where you were going with that now however. If you would weigh your upper receiver with that half of the QRB, and the barrel assembly without the handguard, I'll go through the AR Parts Weight spreadsheet and add up the rest of the components to find the difference.

Diamondback
05-06-23, 21:33
Will do, but the barrel weight is going to be "contaminated" by both the QRB frontplate and the MI mount nut, both locked in by the gas block. (Sorry, it was enough nightmare getting that damn thing on the first time, I paid the extra for drilling and pinning and got "drill but no pin." Fighting with gas blocks... I think that stays on the "Subcontract to Pro" list.)

The complete CRLW-10.5 with nut I used weighs 7.6oz. Barrel is 22oz.

Disciple
05-06-23, 21:43
Thank you, that will do fine.

Diamondback
05-07-23, 18:47
With barrel nut, frontplate and flash hider the barrel weighs 35.16oz. 35.16 - 22 = 13.16oz combined weight of A2 FH/crush washer, MI nut and QRB frontend.

BCG and CH removed but MBUS3 still on, the backplate and upper assembly weigh 12.13oz.

https://cdn.discordapp.com/attachments/655632728812683276/1104901526708834304/image.png
Test-fitting an idea I just had... thinking about dumping the weight and inflexibility of the A3 Tactical rail-to-rail clamp by just asking my pro smith if he can directly braze the ends of two QD optic-risers together for a closer coupling between the halves for both this and the "Bond Movie Briefcase."

Disciple
05-07-23, 22:05
With barrel nut, frontplate and flash hider the barrel weighs 35.16oz.

BCG and CH removed but MBUS3 still on, the backplate and upper assembly weigh 12.13oz.

Thank you. Please tell me if any of this looks off.

8.35oz Aero Precision APAR501603AC assembled upper
1.06oz MBUS3 REAR
2.72oz QRB backplate

1.7oz MI CR/SLH steel barrel nut -- may include 0.2oz torque plate and/or screws
21.8oz Rosco Bloodline 12.5” 5.56 NATO
0.85oz Rosco gas tube (other carbine gas tubes listed at 0.6oz)
1.9 to 2.15 oz A2 flash hider
1.5 to 2.5 oz Rosco 0.750 gas block -- no reasonable weight listed, estimated range
6.2 to 7.9 oz QRB frontplate

Total 2-pin QRB weight: 8.9 to 10.6 oz.

Diamondback
05-07-23, 22:09
Looks like a pretty fair estimate--bear in mind the QRB also uses a proprietary 2-piece gas tube. But about 1/2lb feels about right.

Diamondback
07-03-23, 19:41
Bump with a final update: It. Is. Done. Upper freshly back from a gunsmith tuneup.

https://cdn.discordapp.com/attachments/655632728812683276/1125569041256427571/20230703_154906.jpg

JediGuy
07-04-23, 06:09
Are the accessories on the bottom and top rails clone-specific?

Diamondback
07-05-23, 12:50
Are the accessories on the bottom and top rails clone-specific?

No, they are completely my own, part of a "Product Improvement Program" concept. (Since I couldn't get the G2 rail for a true clone, I went for "how would the USAF build more if needed, and how can we make that better.") The top is just a coupler to join the two pieces together in the bag--doesn't make sense to have to fumble for six pieces in your seat-pan when seconds count in Indian Country if we can try to get it to "grab the rifle and a mag-carrier and RUN, decouple and set up once you've bought distance or other breathing room"--and a Princeton Tec Switch Rail dual mode red/white light. Bottom is a Damage Industries handstop/sling mount with a Lasermax Uni-Max set up to fire through it and a Lasermax tape-switch. I was trying for "rugged but lightweight and compact" additions to improve on the original model while hopefully still ejection-survivable. Spec is Magpul MBUS Pro sights; I upgraded to MBUS 3. (The 10-round mag in the well is not regulation either, but seemed a logical way to achieve a faster time-to-first-shot over having to futz with a mag on top of joining the barrel--this is "lock barrel, rack bolt, safety off, BANG." Safety-off can be skipped if it's packed hammer-down.)

Standard ASDW doesn't have a sling either, as far as I've seen, part of why I went with a 2-to-1 convertible. I have four possible mount points: the end of the Damage Industries buffer tube, the PWS ratcheting endplate, just ahead of the QRB on the Midwest handguard and the handstop at the very front.

Disciple
07-09-23, 10:43
No, they are completely my own, part of a "Product Improvement Program" concept. (Since I couldn't get the G2 rail for a true clone, I went for "how would the USAF build more if needed, and how can we make that better.") The top is just a coupler to join the two pieces together in the bag--doesn't make sense to have to fumble for six pieces in your seat-pan

You mentioned the idea of a folding mechanism earlier. What do you think of the design of the FoldAR (https://foldar.com/product/foldar-mobetta-short-barrel-rifle-12-5-5-56x45-nato-nfa/) that does just that? If it returns to zero after folding it looks like the next evolution of this concept. In addition to keeping the halves together and aligned it is shorter as the upper receiver ends right after pivot pin, and I would bet the built-in mechanism is significantly lighter than an add-on. (The site lists 6.4 lbs for the 12.5" but 6.15 for the 16" so I don't trust their numbers.)

Diamondback
07-09-23, 10:55
You mentioned the idea of a folding mechanism earlier. What do you think of the design of the FoldAR (https://foldar.com/product/foldar-mobetta-short-barrel-rifle-12-5-5-56x45-nato-nfa/) that does just that? If it returns to zero after folding it looks like the next evolution of this concept. In addition to keeping the halves together and aligned it is shorter as the upper receiver ends right after pivot pin, and I would bet the built-in mechanism is significantly lighter than an add-on. (The site lists 6.4 lbs for the 12.5" but 6.15 for the 16" so I don't trust their numbers.)

Were *I* designing from a clean sheet, the FoldAR is more like the direction I would have wanted to go in. However, an ejection is an absolutely brutal experience--per my prof if you have to ride the bangseat you WILL be coming out of it with at least minor-nuisance level injuries--so it would need to be tested for shock tolerance. I'd also assume that USAF Gunsmithing Shop at Lackland was trying to work "on the cheap" recycling as much of already-in-hand M4s s they could.

The other concern is the particular geometry of the seatpan kit's internal volume--for all we know a FoldAR might be too deep; I have no idea where to find dimensions on the kit or a reference sample to work from, and I doubt the boys in blue would respond with anything less than sending their private Gestapo at OSI for a rather unfriendly chat.

Certainly an idea worth exploring someday...

Stickman
07-09-23, 18:03
I like the way it turned out. Very outside the box thinking.

Diamondback
07-09-23, 18:17
I like the way it turned out. Very outside the box thinking.

Thanks, Stick--this project was my gunsmith's last hurrah before they close up shop and flee this blighted Communist zombie-apocalypse hell for Idaho.