Summer Rust 2019: Cheap .22lr AR-15 Folding Stock/Brace Adapter

Folding stock/brace assemblies for AR-15s are pricey, mainly because of the necessity of accommodating the buffer assembly. This is obviously not of importance on .22lr ARs, or any AR-ish platform with some kind of piston mechanism that doesn't require a buffer assembly. While there's options of chinese airsoft LAW folder ripoffs, or ACE adapters, I decided to write up a method using a cheap UTG buffer you can easily find on eBay with AR-15 male receiver threads/female AR-15 buffer tube threads, because I haven't seen any folding solutions in the price range that this project falls under (~$30, assuming you have common household tools and a dremel).

I got my inspiration from this AR15.com forum post mentioning this concept years ago, but did not include a thorough walkthrough on actual fabrication needed.

What you need:

-UTG Side Folding Stock Adapter (TL-K7FAD01), easily found on ebay for $15-20 -AR-15 carbine stock wrench (I like the cheap ones on ebay you can find for ~$6) -Everbilt #10-24x1" screws (Home Depot Online # 204274625) -Everbilt 10-24 nut (Home Depot Online # 204274134) -Octagon Box with 3/4 inch Knockouts (I used this, bought for like $2 at Home Depot, but they don't seem to have it on their website any longer. -Drill w/ 5/32 bit (or something close) -Dremel w/ metal cutting blades -Vice -Dremel griding adapter, or bench grinder, etc. -3/8" wrench or socket (socket works better)

1. Note the two threaded ends of the Adapter, one with internal threads for the buffer tube, and the other with external threads for the receiver. I'll be referring to the latter as the "receiver end" in the next few steps.

2. Cut about 1/2" of threads off from the receiver end of the adapter, this can be shortened later if it's too long, you don't need to be precise. This is what you will thread into the receiver.

3. Cut the remaining threads off the adapter on the receiver end. You do not need this portion of the threads. Use a vice to secure the thread tube to cut easily.

4. Use a Dremel grinder adapter/bench grinder/etc to make the cut end of the adapter as flat as you can.

After these steps, you should end up with this.

4. Thread the 1/2" threads into the receiver until you have enough sticking out the back to use the receiver end plate and the slim castle nut provided with the stock adapter assembly, and place those two on, tightening the castle nut with the stock wrench to secure the threads on the receiver. Try to not thread on too far, as using too much of the threads will cause your screw to not be long enough. Flush is fine, but not required.*

Looks like this.

A good thread length into the lower.

5. Now is a good time to assemble the buffer tube onto the adapter. Doesn't need to be done now, really, but will help with unlocking the adapter halfway in a later step.

6. Pop out one of your 3/4 in. Knockout washers from your metal box, these are the perfect size to secure your lower to your adapter. Now comes the most challenging part: You need to drill a hole in the washer to put a screw through, but it needs to be done at an offset, non-center spot to allow travel of the charging handle above the adapter (this is why you can't just use a washer with a center hole: the charging handle will hit the adapter).

To be honest, I just put the washer inside of the receiver, looked through the rear of the buffer tube threads, eyeballed a good spot, marked it with a sharpie, and drilled. Got it right on the first try!

Pic here.

In the interest of being precise, here are some caliper measurements, if you want to make as close to the same hole as I did:

Hole circumference: .2 in Distance from edge to closest part of hole: .219 in Distance from edge to furthest part of hole: .419 in Distance from edge to estimated center of hole: .322 in

3. Insert screw into the hole already in the stock adapter, and hold it flush with the back of the receiver. Place the washer inside of receiver flush against the cut threads, then push the screw through, threading a nut on with your fingers once enough thread is through. This requires like 5 hands, but you'll figure it out.

4. Rotate the 3/4 washer (and the whole assembly, really) to make sure it's as low on the receiver as possible (for charging handle clearance) and level.

5. Use 3/8" wrench/socket with a screwdriver on the other end to tighten nut until tension holds the stock adapter in place.

6. Ensure the folding mechanism works, and charging handle clearance is adequate. The adapter will still will get in the way of your fingers slightly, but charging handles with large latches will remedy this issue.

7. Enjoy!

Completed pic.

*For cosmetic/fitment purposes, as mentioned in step 2, you can shorten the cut threads to have only what's necessary to go onto the lower threads and to secure the castle nut, making the OAL/LOP shorter (which may be a concern with rifle builds, YMMV) and making the setup more comfortable.