M*CARBO Brotherhood

AR-15 Buttstock Adapter For Your SUB-2000?


@JoeFridaySays I am all out of likes but that was a premium answer with references even!


I don’t do it for the likes. Sometimes a problem intrigues me or I have read something or I just think I may have an idea that will help and I feel the need to get involved, When I saw the AR buttstock problem I remembered seeing the Backpacker solution and mentioned it then realized I could possibly improve on it.
Last night, I realized that while @Dred had been involved in those earlier discussions, the other participants in this most recent dialogue had not and therefore did not know of this possible solution to the folding problem…so I pointed it out to them. :grinning:


@JoeFridaySays I know you don’t…but it is a way for members such as myself to show our appreciation for your valuable input and unique insights!

(I think you may have single handedly revitalized the entire S2K modifications threads with your forend designs and graphics abilities!)

I was just brought up to say thank you!:+1:


Your thank you is appreciated and you are welcome. I am getting ready to post a new illustration in the forend thread that should be more typical of most users; then I unfortunately have to do some real work this weekend.
But this has been fun and hopefully has provoked some thought and may even result in a new product - although I thought that of the buttstock adapter as well given the interest expressed by Chris and his team.


@JoeFridaySays oh you have “provoked some thought” and then some with your graphics ability!

To be honest the S2K mods were getting a bit stale…you put in all the available MCARBO parts and then what?

Then YOU CAME ALONG and gave us a bunch of fresh ideas!

A big :+1: brother!


Hey @Texprep

I’m gonna leave this here for you to ponder. Worlds easier and solid concept easily adapted to the sub 2000:


Wow! That was nice to wake up to!:heart:


@Dred Buttstock Adapter
At least this one actually exists. The downside is you are stuck with the one stock.
I posted a design similar to this several months ago (updated below) that would allow you to use any stock you wanted. @Dred and some others had input in refining the design that I am trying to get made as the ability to mount different stocks would be a nice feature and the OEM stock sucks.

3D Printed Butt Pad

Funny that I started mine with all the parts to build the design @JoeFridaySays shows. I just landed where I did based on what I thought and considered with the parts in hand.

If I remember, next time I’m at the hardware store, I will grab a few bits I need to mock the ELF for a S2k implementation. I happen to have a bar slide stock in my pile on unused parts and I have ideas. In my case, I’ll be sticking with my Minimalist, but …


Hey Dred, I like that. Have all the parts I need to do what you did to your stock but haven’t found the time to do it yet. Seems like my machine shop customers have decided to spend all their remaining budget before the end of the year, shop is swamped with work.

Do you have a link for that stock? I’m definitely interested.


That looks pretty sweet. Doesn’t look padded though so I’m not sure how much more comfortable it would be. Anyone richer than me want to try it and report back?


@TheThreeLaws I would have to agree I don’t see what you would gain with that. @Dred yours is miles ahead of that. I get ease of use and all that but it does look uncomfortable.


@TheThreeLaws and @Flogrown

Y’all don’t think the minimalist is padded?? It’s not. But the shape and location make a difference.

The stock I posted is a concept piece. The charging handle would wack it goodunless you have longer gorilla arms than me.


@Dred I kinda do have gorilla arms hahaha, length of pull was kind of an issue for me at first. That’s why I added the gen1 hand gaurd to my forend to get my long arms some relief. My buttstock pad adds a little more than 2" to the overall length as well


I really think just location, surface area, and the amount of material in the stock will make for a much more pleasant shooter…without any padding! :+1:


It’s made by Elftactical:

Elf Tactical Minimalist Stock

I might have to pick one of those up after the New Year to try on a couple of our lightweight AR builds. While I have it, might as well try it on the S2K, too.

Elf Tactical makes great products. We have their push-button AR safeties in just about every AR we have. It doesn’t work well with drip-in triggers, so we do have one with a drop-in that we have the regular switch-type safety, but on the others, they’re all push button.


I like that design. It actually moves the weapon up some from the shoulder, allowing a better sight angle with factory sights. That was an issue we immediately discovered with our first shot of our S2K; you had to get your head at an uncomfortable angle to look down the sights properly. My wife actually cut her cheek on some casting flash that was on the latch because her face was laid over it when she shot.

The only issue I see with the current setup is you may need to mill the top of the top tube flat in front of the latch, since there may not be room for it and the top of the hand guard and still allow the rifle to be latched shut when folded.


You could be right and I would expect a lot of things to pop up as the design is translated into reality. At the same time, you have almost 1/8" of space between the folded sections and while that is small, it will accommodate a pretty thick piece of metal. Considering the length of the upper tube, it should not have to be particularly thick to have sufficient strength for the job, especially if made of steel - possibly even with small reinforcing crimps or ribs.


I’m new here, is there another, replacement buttstock thread? That would be my preference over an adapter. I’d really like to see a custom MCARBO stock, very similar to the sub 2k’s factory stock, but with:

  1. the ability to attach Magpul rubber butt-pads.

Want to keep your sub2k compact? Use this one that’s 0.3" thick.

Want to reduce recoil more? Use this 0.7" one.


Want to increase length of pull more, get an extended butt pad, etc.

  1. A little more room, so a second Recoil Buffer can be added. (If that’ll help reduce recoil more than just 1).

I think MCARBO can get this to market faster vs having to develop the pad as well. More ways to mitigate recoil gives more customization options. For those that want their PCC light, skip the heavier charging handle and bolt. For those that want the softest shooter, add those with a soft pad too. Lastly, better to not require any changes to existing tube, I think a LOT more stocks will sell with easy install.


Why not mold a piece of metal with the serial number into the polymer like on a glock frame?