Help me find an optic/mount for a specialized AR?

[Diamondback]

Guys, I'm stumped on this one, so I'm crowdsourcing it. Need ideas for an RDS and mount that both co-witnesses with an F-marked FSB from a .4375" riser (Vltor CASV handguard), and flips to the side. I'm thinking an Aimpoint ACO or PRO for an optic, but don't know of any mounts that combined co-witness and side-fold--wonder if there's someway to rig a magnifier mount to hold zero and still flip for stowage.

Gremlin's already 6" top to bottom folded without optic, and I'm trying to keep it as compact as possible while still being combat-ready with a few flips of wrists to unfold and a tap on the BUIIS release button.

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[Diamondback]

OK, talked to the guys at Larue and they say the only reason magnifiers can flip is they don't need to hold zero. Did a little digging to refine things, took some measurements and came up with some numbers and a few things that fit. Some of this is restatement of previously mentioned, but I'm copying something I'm also crossposting on another site and why reinvent the wheel?

Application: Weapon is a pistolized Mk 18 Mod 0 EOD, with Vltor CASV rail.
Mission: GHB/Briefcase/Discreet Carry PDW, something to give an in-between option between a sidearm and a full patrol carbine. Expected engagement range no more than 300m, mostly urban/Close Quarters. Primary requirements are discreet and rugged--as something that'll live in a Go-Bag fulltime with other heavy gear, the optic will need to take a fair amount of knocking around. Discreet, I'm not sure which would be lower risk of a "YO LOOK GUN HERE SHOOT THIS GUY FIRST" print between the corner of a pistol-size mini-reflex like a Docter or a Trijicon RMR or the longer but more gently rounded tube of something like an Aimpoint ACO or PRO--CompM4 means obvious extra bulge from the battery compartment, ACOG ain't happening and is both outside my budget range and overkill with all its drop-compensation.

If my math is correct, with my Diamondhead BUIS having a focal height of about 38.5mm and the CASV riser being about 12.5mm, that means an adjusted focal height of 26mm for Absolute co-witness, I'm figuring around 5mm more for Lower 1/3. Rub is, every factory optic/mount combo I've looked at comes in anywhere from 1 to 6mm low--and low on an FSB gun means trying to see through the tower. How far off the intended focal height is "too far"? Absolute would give me the closer fit and lower profile I like, but anything from slightly-high to lower-third would give me some separation. Not sure how to decide here, since almost all my meager experience is irons.

I've found a few options starting from factory mounts that look like they'd work as possible options, but haven't really waded into aftermarket mounts yet building my spreadsheet, so I thought I'd ask you guys for recommendations on four scenarios trading up from "Starter" to "Value" to "Better" to "Best." "Starter" would eventually be consigned to range use only on another build, something like a Bushnell TRS25, "Value" being a little higher but still moderately priced, a not-first-choice-but-pretty-good-for-the-price. "Best" would be like Trijicon or Aimpoint CompM4 level. "Better" would be maybe not Mil/LE Issue, but something where if your Top Tier choices were off the table you'd consider it an "acceptable in-a-pinch substitute"--better capability/quality than Value but better price than jumping straight to Spare No Expense.

Known options for Absolute: (lower mounts higher on list)
on height Aimpoint Micro T-1 or T-2 in Larue LT661
+4mm Aimpoint PRO factory mount (no spacer)
+4mm Aimpoint CompM4 factory mount (no spacer)


Known options for Lower 1/3:
on height Aimpoint ACO in Larue LT152
on height Aimpoint PRO in Larue LT152
If I could get a 1/4" Picatinny riser like the old YHM-220 a Trijicon MRO on a Trijicon AC32067 mount would work here too.

 

[Kruel J]

I prefer lower 1/3. YMMV.

 

[Diamondback]

OK, here are some options I've found... would appreciate anybody with experience's thoughts on these. Numbers are distance high/low in mm, highest mounts to top, and I'm excluding anything outside of 1mm off target-height (1/2mm low on Absolute).

Lower-Third:
+1.00 Aimpoint PRO factory mount; Aimpoint CompM4 factory mount no spacer
+0.97 Aimpoint ACO/PRO with Primary Arms PAMEDRING
+0.21 Aimpoint Micro T-1 with ADM T1-CAS-V
-0.04 Aimpoint ACO/PRO with GG&G 1067
-1.00 Aimpoint ACO/PRO with Badger 306-17
-1.00 Aimpoint ACO/PRO with GG&G 1020
-1.00 Aimpoint ACO/PRO with Larue LT661
-1.00 Aimpoint ACO/PRO with ADM AD-68L

Absolute:
+1.00 Aimpoint Micro T-1 with Larue LT661
+0.40 Aimpoint ACO/PRO with Badger 306-21
+0.00 Trijicon MRO with Trijicon AC32067
-0.36 Aimpoint ACO/PRO with Vortex TRM
-0.48 Aimpoint ACO/PRO with Warne 214

Anybody else have any suggestions for getting a red-dot at either 25 or 28mm rail-to-reticle on-the-dot?

 

[dwaineshort]

Aimpoint comes with different spacers, and the vortex magnifier comes with a flip mount.
I use to run a Eotech and a n Aimpoint T1 with the Aimpoint magnifier.
Hated it traded for an Acog and added a rmr. Wasn't a big fan of that set up and switched to a 1-6x Leopold vx6 cmr-2 and never looked back.

 

[Diamondback]

Thanks, Dwaine--don't think an ACOG will mount low enough for this build and it might have problems with the fixed FSB for co-witness, and even Aimpoint's lowest spacers are too high while no-spacer bare mounts are out-of-bounds low yet too high for any Picatinny riser I've been able to find. No magnifiers involved, this is strictly a CQB/PDW pistol.