K … so … let’s say you need one of these tomorrow - that is: you can’t wait for @ChrisNelson to offer a professional grade example if he’s gonna hook us up. Note: I’ll buy one just to hide all the sins staring y’all in the face here.
We are looking at a slightly modified AR 15 carbine length buffer tube - $10 to $20.
For starters, I had to cut it to the length I wanted. If you look at the bottom of the tube, you will find a track that allows 6 LOP settings. In my case, I cut the tube exactly where the track began. If you are familiar with the M*Carbo bolt tube cover - I retained the full length on the cover and the remainder of the AR tube is butted right up to the bolt tube cover.
Ok, the Mil spec AR buffer tube does not just “slip” over the Sub 2000 bolt tube. I chose to use a brake cylinder hone (auto parts store/Snap-on Truck or Amazon - get one with 1" in the operating range) to grow the inside diameter of the buffer tube until it just slides over the bolt tube. I was careful to stop before I created a sloppy (ultimately noisy) fit. Honestly, it didn’t take much care 'cause I went through a fully charged 4 hour capacity Lithium Ion battery on my hand drill - that’s a couple hours of “honing.”
We know that we access the bolt through the bolt tube. So, we need to create a means of installing the bolt stop with the cover in place. This was pretty easy even if my metal work suggests differently. I will leave you to your devices on how to create this access. I used a combination of cutoff wheels, grinder and files.
Bolt stop pin:
This will require the greatest degree of precision. You need a hole put clear through both sides of the AR buffer tube which lines up perfectly with the holes in the bolt tube. Admitedly, I struggled with this - largely, because I refused to measure or mark anything. I started with a small hole which successfully hit one side of the bolt pin hole then I carefully grew the hole until I had a match on one side. Then … I crossed my fingers and drove the hand drill right through the second side of the buffer tube. Full disclosure: I was less than perfect and I will be watching my stop pin carefully.
Yes, the Minimalist stock has a QD sling mount directly ahead of the adjustment lever.
I cut the lock point off the top of the factory bolt stop so that it can be fit into place through the access cutout. I used a 3/8" clevis pin in place of the factory bolt stop pin so that I didn’t have to shave down my factory pin in case I wanted to return it to factory configuration.
I’m done. But, I could go about making a cutout on the bottom side of the buffer tube to allow the front sight to slip through. If you look at my previous post with pictures, you’ll see that it does not fold completely. The front sight is preventing a complete fold where it is impeded by the bottom of the buffer tube. Since I’m not certain I’m keeping the front sight … I’m not clearancing further. But, for those that do, or those that will … I still have the latch portion of the bolt stop. I could attach this to the top of the Minimalist and use the adjustment lever to “lock” it closed. I’m not doing this 'cause it would cost me about an additional second to deploy it and it’s a defensive tool. If I discover that I’m banging it up due to lack of latch - of course, I will revisit.
I estimate my length of pull to be the equivalent of the factory stock fully extended plus the ATI recoil pad. This is just what works for me, and there are shorter and longer settings available for other shooters. It must be returned to this length configuration to tuck the rear sight through its hole in the buttstock - this way it is ready when I unfold it.
I have not put a ruler to anything. If you want measurements, describe what you want and I will measure for you. I can tell you that I would have to clearance for the charging handle to run this stock at the shortest length of pull I can select. I fired it at the shortest setting without problem, but I wasn’t going to be able to lock the bolt back. The charging handle did hit the buttstock but nothing cracked or fell apart, so …
Finally, if I had to start anew, I would start with a Commercial spec buffer tube and stock. The commercial spec has a slightly larger inside diameter and the “honing” should go faster as there is less material to remove.