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

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.

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.

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."

If you get/have a picture, I’d love to see one for those.

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Originally Posted by JediGuy

If you get/have a picture, I’d love to see one for those.

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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.

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.

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?

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.

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.

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Originally Posted by JediGuy

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.

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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...

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.

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Originally Posted by Hammer_Man

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.

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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.

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Originally Posted by Diamondback

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.

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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.

Quote:

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Originally Posted by Hammer_Man

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.

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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.

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/f769949c...2edb3049b1.jpg


https://66.media.tumblr.com/e8a98e71...f86662aea7.jpg


https://66.media.tumblr.com/f326f124...0f8a0f6d01.jpg

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/413387ca...64ef4f6bf7.jpg

https://66.media.tumblr.com/6f01379d...1edde4b50e.jpg

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?

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Originally Posted by Stickman

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.

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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.

Attachment 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...)

Quote:

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Originally Posted by JediGuy

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?

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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".

Quote:

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Originally Posted by Stickman

"Stick sucks, we should just carry Mk18s".

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

https://www.operationparts.com/kac-k...flip-up-sight/

FYI URX II in stock at Operation Parts

Dusting off and updating now that Midwest has discontinued the G3ML10.5 rail and complete ASDW uppers...

Component	Common	Vendor/Cost	ASDW Specific	Vendor/Cost	GL/SSC Specific	Vendor/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		???

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/attachmen...103_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).

Should be cool once it’s together. And even if the local FFL doesn’t have the lower you want, prices are down everywhere and it’s Sale Season..,

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.

Quote:

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Originally Posted by Diamondback

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.

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

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Originally Posted by Disciple

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

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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."

Modular backends?

Would a 15-round magazine be about the same height as the folded grip?

Quote:

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Originally Posted by Disciple

Modular backends?

Would a 15-round magazine be about the same height as the folded grip?

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"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.

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.)

PIP component-coupler installed as a test fit:
https://cdn.discordapp.com/attachmen...109_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.

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/attachmen...122_143100.jpg

https://cdn.discordapp.com/attachmen...122_143309.jpg

https://cdn.discordapp.com/attachmen...122_143527.jpg

What is the assembled length of the unbarreled upper mounted on a carbine-extension lower?

Quote:

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Originally Posted by Disciple

What is the assembled length of the unbarreled upper mounted on a carbine-extension lower?

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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. :)

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/attachmen...123_185801.jpg
https://cdn.discordapp.com/attachmen...123_185915.jpg

Quote:

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Originally Posted by Diamondback

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...

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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.

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/attachmen...124_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...

Now that the case and mag pouches are in...


Boring messenger bag/manpurse, right?
https://cdn.discordapp.com/attachmen...202_132059.jpg


SURPRISE!
https://cdn.discordapp.com/attachmen...202_132206.jpg


But wait, there's more!
https://cdn.discordapp.com/attachmen...202_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.

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/attachmen...207_202624.jpg

https://cdn.discordapp.com/attachmen...207_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.

Coming together nicely. Are you staying with the bare receiver extension?