AR buffer tube options for Sig SBX brace on a non-AR device... school me?

[Guest mechanically]

Help me oh wise AR builders... I know nothing about ARs!

I've got a CZ Scorpion Evo in the mail. (!!!)

I want a folding SBX brace on it for compact carry, and to use should I need better precision one-handed, or something.

So, I guess I have options?

CZ will have an adaptor on the market in a couple weeks for a buffer tube. Obviously, there's nothing inside, so I can "hinge it" any way I want. I just don't know what I want!

Shortest overall length when folded is important to me.

I presume the hinge needs to have male ends to screw into the back of the pistol, and female threads for the tube itself. Am I missing something?

Since the hinge in that scenario would add length, how long should I want my buffer tube to be? I'm a big guy, so maybe longer is better?

Below is a photo from CZ USAs Facebook page. (Apparently, that "saddle," like the SBX, is "not a stock?" Interesting...)

So, how would you hinge it?

[Oh Shoot]

....

CZ will have an adaptor on the market in a couple weeks for a buffer tube

 

Well, there's your answer about how to get to buffer tube to fit a brace.

 

As far as hinge for folding, pretty limited options without going to some AK type folding stock adapter that requires machining into the receiver, who knows what you'd get into trying to do that with Scorion, but didn't do search, maybe folks have done it.

 

However, one easy way is that there is a common adaptor that goes between tube socket and tube. Sold by several companies but seems it's all the same Chinese product. I bought mine from US Machinegun:

http://www.usmachinegun.com/proddetail.php?prod=YGO-ARFLD

 

But turns out it seems to be same thing marketed by UTG for cheaper:

http://leapers.com/prod_detail.php?mitem=Accessories%20and%20Parts&itemno=TL-K7FAD01

 

 

 

 

Only diff is that the UTG/Leaper's one, doesn't seem to come with a castle nut which you really need to lock it down on the male end, no biggie, 4-5 clams.

 

Works "okay". Meaning, it's rock solid side to side, but significant wobble up and down. On the plus side, doesn't seem to matter at all should the brace be misused against the shoulder. There really doesn't seem to be an "inline" better folding adapter anywhere on the market.  You can use any buffer tube you like, some are better suited for the SIG braces than others, that's a KAK on mine made specifically for the SB15 brace, but used it with the SBX brace in this case with small spacer.

 

As far as length, "pistol" buffer tubes only come in narrow range of lengths, from ~ 7" to 9.5". You can get more length from end of actual brace by using a couple different spacer type things to extend it off the back of the tube.

 

 

 

- OS

Edited January 15, 2015 by Oh Shoot

[Clod Stomper]

Thread hijack/dumb question:

Does that hinge adapter allow a standard tube to hinge on an AR and still function when extended? I haven't seen one of those in person.

[Smith]

Thread hijack/dumb question:

Does that hinge adapter allow a standard tube to hinge on an AR and still function when extended? I haven't seen one of those in person.

No. Law Tactical makes the only hinge/buffer tube that works with an AR (that I know of).http://www.lawtactical.com/

[Oh Shoot]

No. Law Tactical makes the only hinge/buffer tube that works with an AR (that I know of).http://www.lawtactical.com/

 

Right. The adapter I mention would only work with a piston type or blowback AR that doesn't require receiver buffer/spring.

 

The newest iteration of the Law does allow a single shot to be safely fired from closed position, previous versions would likely trash it if fired closed.

 

- OS

[Clod Stomper]

Cool, thanks.

Whew that's pricey.

Sorry for the hijack.

[Dolomite_supafly]

Buy this, it goes into the back of the receiver:

http://riflestocks.com/store/product27.html

It is what the hinge attaches to.

 

Here is the ring to lock the above in place:

http://riflestocks.com/store/product108.html

 

Then buy this hinge:

http://stormwerkz.com/stock-folding-mechanisms/stock-folding-mechanism-ar-type/

 

Then screw the buffer tube into it.

 

That is about the shortest you are going to get a folding stock on that gun. I am about to do the same to a dedicated 22lr AR.

 

 

[Guest mechanically]

 

However, one easy way is that there is a common adaptor that goes between tube socket and tube. Sold by several companies but seems it's all the same Chinese product. I bought mine from US Machinegun:

 

- OS

OS, that is EXACTLY what I was imagining, but hadn't yet found. As always, your skill in communicating so well is a huge assist!

 

Sorry for the hijack.

No worries, I'm glad you asked too!

 

Buy this, it goes into the back of the receiver:

http://riflestocks.com/store/product27.html

It is what the hinge attaches to.

 

Here is the ring to lock the above in place:

http://riflestocks.com/store/product108.html

 

Then buy this hinge:

http://stormwerkz.com/stock-folding-mechanisms/stock-folding-mechanism-ar-type/

 

Then screw the buffer tube into it.

 

That is about the shortest you are going to get a folding stock on that gun. I am about to do the same to a dedicated 22lr AR.

Ok, that's also REALLY intriguing. I had come across the Stormwerkz hinge when considering options for my VZ58 pistol, with the same objective of folding the SB15, just haven't gone all the way yet. 

 

So, that Ace Receiver Block... It looks like the "egg shaped" plate has a protrusion that fits into the little hole underneath the threads where the buffer tube screws in. I'm just not certain the Scorpion adapter has "both" holes. (The threaded buffer hole, and the smaller one beneath.)

 

Or, maybe ALL adapters have both holes, and have something to do with preventing your stock from spinning around? Like I said, never built and AR myself...

 

 

So the Ace Block would screw to whatever hinge you're using, the egg-shaped plate goes next, and it's keyed to keep things from spinning when they shouldn't, and the locknut goes inside the receiver/adapter to keep everything connected? 

 

Assuming I've got that right, that's also very promising! Thanks Dolomite!

[Oh Shoot]

.....

So the Ace Block would screw to whatever hinge you're using....

 

The Ace receiver block threads straight into an AR15 receiver first, and an end plate would keep it from turning once locked down with castle nut or the thinner nuts they make just for it. (actually this pic has the end plate reversed, seems, as the projecting nub would actually face inward into hole for it in receiver).

 

 

 

 

and the hinge bolts onto it, then of course the buffer tube screws into that.

 

I just didn't know anything about the Scorpion -- but seems it doesn't have threaded AR type receiver extension hole in the rear with the end plate nub cutout also? If not, dunno how this could work, but will let Gordon explain what I'm probably missing.

 

edit for afterthought:  He said block goes into "back of receiver", but maybe he meant you would screw the Ace block into your Scorpion buffer tube adapter, however that attaches to the rear of the firearm? But would still need a place for the end plate to grab into, or the base could still turn, seems.

 

I'm lost on it, but I'm sure he can explain what we're not getting.

 

- OS

Edited January 16, 2015 by Oh Shoot

[Dolomite_supafly]

You just omit the receiver end plate on the pig nose install. It is not needed to keep the pig nose from turning if you get the mini castle nut tight or use Loctite.

 

I bet you have a couple of buffer tubes held in place with only a castle nut and without the receiver end plate. Just because it is included does not mean it MUST be used.

 

Screw the pig nose in until there is just enough room for the mini castle nut. Tighten it down and make sure the pig nose is square. Then attach the hinge to the pig nose then add the buffer tube of your choice. And with the hinge you could use the end plate if you do not have one.

[Oh Shoot]

You just omit the receiver end plate on the pig nose install. It is not needed to keep the pig nose from turning if you get the mini castle nut tight or use Loctite.

 

I bet you have a couple of buffer tubes held in place with only a castle nut and without the receiver end plate. Just because it is included does not mean it MUST be used.

 

Screw the pig nose in until there is just enough room for the mini castle nut. Tighten it down and make sure the pig nose is square. Then attach the hinge to the pig nose then add the buffer tube of your choice. And with the hinge you could use the end plate if you do not have one.

 

Gotcha. So, helping out Mechanically -- Scorpion Buffer Tube adapter -> pig nose -> hinge -> buffer tube. Right?

 

Same as I did with AK above, but with one additional part, and a better hinge I assume.

 

- OS

Edited January 16, 2015 by Oh Shoot

[Guest mechanically]

OS and Dolomite, when are you guys coming to town so I can buy a root beer? Seriously. At least a soft pretzel? 

Sheesh this has been helpful. 

 

 

 

Hey, poling around the ACE site, I found this. Looks a LOT like the Stormwerkz, and would save shipping from two vendors. Think it's as good as the Stormwerkz unit? Same price, even...

 

http://riflestocks.com/store/product106.html

[Guest mechanically]

Breaking news... While it's not for sale yet, CZ has put the adapter on the website.

 

http://shop.cz-usa.com/ProductDetail/19992_Scorpion-Evo-3-S1-Pistol-Arm-Brace-Kit

 

Here's the description:

 

 

 

SCORPION EVO 3 S1 PISTOL ARM BRACE KIT

ENABLES THE ADDITION OF AN AFTERMARKET ARM BRACE OR
OTHER PISTOL BUFFER TUBE ACCESSORY

ADAPTER IS MADE OF 6061 T6 ALUMINUM, FLAT BLACK ANODIZED

BUFFER TUBE MADE BY KAK INDUSTRIES SPECIFICALLY FOR FITMENT
OF AN AFTERMARKET ARM BRACE
THREADS ON ADAPTER (1-3/16x16) ARE STANDARD TO ACCEPT ALL
AR-15 BUFFER TUBES/RECEIVER EXTENSIONS

IF USING A BUFFER TUBE OTHER THAN THE SUPPLIED KAK INDUSTRIES TUBE
THERE ARE TWO THREADED ALIGNMENT HOLES (10x32 THREAD) FOR TUBES
THAT USE A NOTCH FOR INDEXING. A 3/16 HALF DOG SOCKET SET SCREW
WOULD BE USED FOR PROPER INDEXING.

GUNSMITH INSTALLATION IS RECOMMENDED

 

The 2nd to last paragraph is interesting... I looked up "3/16 half dog socket set screw" and it looks like something that would come on the Ace adapter Dolomite shared above...

 

I think I'm off to the races here, thanks again for all the help. Just thought I'd share the text above in case it shed more light on the best way to hinge the tube, assuming you actually know what that paragraph means!

 

Shoot, after this I may as well build an AR, since I've learned so much from you guys!

[Dolomite_supafly]

Forget about the ACE hinge, I have had two separate versions of their hinges and they both began to wobble almost immediately. The Stormwerkz hinge is as solid as they come.

[Smith]

Forget about the ACE hinge, I have had two separate versions of their hinges and they both began to wobble almost immediately. The Stormwerkz hinge is as solid as they come.

This. The ACE hinge was the first and for a long time only option. The Stormwerkz is indeed a better option than the ACE.

[Oh Shoot]

Breaking news... While it's not for sale yet, CZ has put the adapter on the website.

 

http://shop.cz-usa.com/ProductDetail/19992_Scorpion-Evo-3-S1-Pistol-Arm-Brace-Kit

 

....

 

 

The 2nd to last paragraph is interesting... I looked up "3/16 half dog socket set screw" and it looks like something that would come on the Ace adapter Dolomite shared above...

 

 

 

Looks like they're not gonna sell the adapter without a tube. That is KAK's original tube made specifically to fit the SB15.

 

 

I see you were looking for the SBX brace in Trading. No biggie, but note that it has captive end and is slightly shorter in tube channel and won't quite reach the flanged collar on the tube. Doesn't matter as to functionality, just looks a bit odd to some. I used the second KAK version of same on my AK shown previously, but used the short KAK spacer just to fill the gap.

The KAK SB15 tubes are about 1.5" longer than a standard "pistol" buffer tube, which is good on most AK pistol configs if incorrectly used against shoulder as it increases length of pull.  The second one is designed to use castle nut, and has the "channel" referred to in the Scorpion description. On an AR, the channel is used to align with the receiver end plate, which does two things: with a carbine tube it aligns it properly to accept an adjustable position stock, and with all tubes it holds the receiver end plate against lower receiver to contain the spring and detente for the rear take down pin.

 

Adjustable stock position carbine buffer tube:

 

Notice the "channel" through threads.

 

 

Normal end plate looks like this (the "tooth" is what fits in tubes with a "channel".

 

 

 

But there are lots of others, usually used for sling attachments of various sorts:

 

None of those factors are really very pertinent to the Scorpion.

 

Anyway, that is all to say, the tube that comes with the adapter might be fine for your purposes, but there are numerous other choices too.

 

Both SIG braces are designed for tubes that are 1.0-1.2" in diameter. But some are slightly larger and the brace can be a bear to get on there, and also will stretch it out so that it may no longer fit a different tube without some tape or something around it or something. The KAK tubes are perfect for fit in that respect.

 

- OS

Edited January 16, 2015 by Oh Shoot

[Dolomite_supafly]

Didn't think the buffer tubes for the Sig brace had the cutout for the "tooth". At least the 3-4 I have bought never did. I would just tighten them down tight then lock that in with the castle nut.

 

And with the recent ruling it makes the Sig brace useless unless you are shooting it one handed.

[Oh Shoot]

Didn't think the buffer tubes for the Sig brace had the cutout for the "tooth". At least the 3-4 I have bought never did. I would just tighten them down tight then lock that in with the castle nut.

 

The KAK "super" (the second version for use with castle nut) has the channel cutout.

 

The original does not, of course, as it is designed to screw all the way in flush to the flange.  As a matter of fact, the original is sized exactly for a milspec thick end plate (tab is removed from one from KAK or you have to file it off others), some thicker "tactical" ones won't allow tube to reach the buffer retaining pin, one of the complaints that prompted them to make the traditional castle nut model.

 

 

- OS

Edited January 16, 2015 by Oh Shoot

[Ron Padilla]

To sort of resurrect this post for a moment, the Law is the only option then for the AR?  If so has anyone here used one on an AR as I am interested in how it works, I have seen the videos, but, I would like to install one on my pistol build so that it would fit in a back pack.  Just not sure if it would work with a JP scs, I thought that i had read that someone had used one just cant remember where, thanks for any info

[Oh Shoot]

To sort of resurrect this post for a moment, the Law is the only option then for the AR?  If so has anyone here used one on an AR as I am interested in how it works, I have seen the videos, but, I would like to install one on my pistol build so that it would fit in a back pack.  Just not sure if it would work with a JP scs, I thought that i had read that someone had used one just cant remember where, thanks for any info

 

What is a "JP scs"?

[Dolomite_supafly]

What is a "JP scs"?

Silent Capture Spring.

 

It is the new buffer system that uses 1911 type springs to tune. Supposedly quieter than a standard spring.

[Ron Padilla]

Gordon, I saw the one you built, are you still using that one or have you gone back to standard spring and buffer or are you strictly using AK's?  But back to subject still would like to know if anyone has used the law swivel with anything other than a stock buffer and spring?

 

Thanks

[seez52]

Well, there's your answer about how to get to buffer tube to fit a brace.

 

As far as hinge for folding, pretty limited options without going to some AK type folding stock adapter that requires machining into the receiver, who knows what you'd get into trying to do that with Scorion, but didn't do search, maybe folks have done it.

 

However, one easy way is that there is a common adaptor that goes between tube socket and tube. Sold by several companies but seems it's all the same Chinese product. I bought mine from US Machinegun:

http://www.usmachinegun.com/proddetail.php?prod=YGO-ARFLD

 

But turns out it seems to be same thing marketed by UTG for cheaper:

http://leapers.com/prod_detail.php?mitem=Accessories%20and%20Parts&itemno=TL-K7FAD01

 

 

 

 

Only diff is that the UTG/Leaper's one, doesn't seem to come with a castle nut which you really need to lock it down on the male end, no biggie, 4-5 clams.

 

Works "okay". Meaning, it's rock solid side to side, but significant wobble up and down. On the plus side, doesn't seem to matter at all should the brace be misused against the shoulder. There really doesn't seem to be an "inline" better folding adapter anywhere on the market.  You can use any buffer tube you like, some are better suited for the SIG braces than others, that's a KAK on mine made specifically for the SB15 brace, but used it with the SBX brace in this case with small spacer.

 

As far as length, "pistol" buffer tubes only come in narrow range of lengths, from ~ 7" to 9.5". You can get more length from end of actual brace by using a couple different spacer type things to extend it off the back of the tube.

 

 

 

- OS

do you think the wobble on the UTG folding mechanism is just due to the design and general poor quality of Chinese stuff? The other options end up getting close to a hundred bucks so $25 is attractive.

Edited March 8, 2015 by seez52

[Oh Shoot]

do you think the wobble on the UTG folding mechanism is just due to the design and general poor quality of Chinese stuff? ..

 

Guess so. But it does lock up effectively both open and closed. And as I mentioned, once against the shoulder, the play doesn't seem to really matter as for function. Certainly not wonky enough that I personally would likely pay 4 times the price to better.

 

If it ever gets so bad it hinders effectiveness, guess I might go another route. Or just forget the folding part entirely and run straight buffer, as the grip adapter is rock solid.

 

- OS

Edited March 8, 2015 by Oh Shoot

[seez52]

actually I was considering putting one on a Keltec su16 that has a buffer tube stock