I put my SBR'd Charger into a Blackhawk Axiom pistol stock. Sawed a right angled chunk out of the end, and mounted a Stormwerkz AK pushbutton hinge and AR buffer tube adapter to it with some nuts epoxied into the Axiom, and added a Battlelink minimalist stick to the AR buffer tube.

I'll add pics when I get home.

Sorry, I haven't gotten to take a picture of it yet,

Here it is when it was mocked up with a Sig Brace while I was waiting on my Form 1 to come back. So it wasn't tight yet and had a slight bend to it.



And here it is folded.



I'll try and dig it out of the safe and post it with the Mission First Tactical minimalist stock it wears now.

(edit) and use a camera better than a potato.

That looks sharp!

Sorry it's so late, but here's the finished SBR with the MFT Battlelink Minimalist on it.

Extended:



Folded:



And here's a closeup of the rear with the open Stormwerkz pushbutton hinge mechanism, and how I cut the rear tang of the Blackhawk Axiom Charger stock to fit the hinge. The curved groove to the right is the channel that allows the post from the pushbutton to clear when it's swinging open. To create mounts for the two 10-32 hex-head button screws, I drilled two holes just big enough for two deep nuts, I cut some teeth into the outside of the nuts so they'd have "grab" and then put them in with 2-part epoxy. I wouldn't try to but-stroke someone with it in melee combat, but otherwise, it's rock solid. The open air you see through to the trigger guard is how the Axiom is made, the hole in the center of the grip is a molding void from the factory, and the bump from the bottom end of the button mechanism fits right in there.

My advice is to measure it out, and then use masking tape to get your lines square, and go slowly either with a hacksaw, or fine-toothed kerf saw.

Then dry fit the hinge, mark your screw holes for centers, and carefully drill out two holes for deep nuts/coupling nuts like these: https://www.fastenal.com/products/details/0170895

Can't remember the depth of the coupling nuts I used, but grinding down the ends so they don't interfere with the rear of the receiver would be pretty easy if they're too long.

I set up mine to fold on the right, since I figured if I ever slung it, I'd not want the bolt charging handle to dig into my back anyway.

(edit) Sorry, forgot the rest of the build details:

Kidd Engineering 6" stainless barrel.
Kidd Engineering bolt buffer pin.
Kidd Engineering quick release bolt lock.
Kidd Engineering guide rod and spring.
Tactical Solutions long mag-release lever.
Ruger BX trigger pack.
Gemtech Outback II, sealed, not the "D" for Disassemble, but I got it at a good price from a FFL/SOT friend who had a customer bail on it. I'm sending it in to Gemtech for the $25 jailbreak/monocore upgrade though.
Original Charger knockoff Harris bipod.
Stormwerkz push button hinge assembly.
Ace AR buffer tube adapter.
PSA milspec 6 position buffer tube.
MFT Battlelink Minimalist stock.
The Bushnell Trophy red/green dot does the job, but I'm going to upgrade that sooner or later to an Aimpoint T1 style, or mini reflex sight of some kind.

Yeah. $250...