[Mark]

I finally got to replace the side folder on my 522 using the adapter from Double Diamond LE Supply. Following is a report:

Tools Needed:
* Bench vice with lower receiver block or other gun vice
* Soft bench vice inserts (or a third hand)
* 3/32 and 1/8 roll pin punches and holders
* 3/32 and 1/8 flat pin punches
* Prick punch (to stake castle nut)
* Small ball peen hammer
* Stock wrench (for castle nut)
* Lithium grease and brush applicator

Additional Parts Needed:
* Stock lock ring (castle nut)
* Receiver end plate
* Stock tube (commercial or mil-spec)
* Stock (plan to install Magpul CTR)

All parts listed above were purchased at Brownell's (for about $40. Total cost for the project will be a not very cheap $240. However, the plan is to make my 522 match the ergonomics of the 556 with using the same furniture on both.

The adapter ships with replacement pins as needed and an additional roll pin to capture the hinge pin, which the SIG side folder does not include. Installation was simple and straight forward with no traps discovered. The only challenge is that you need a third hand or soft jaw bench vice to compress the latch while installing the retaining pin.

Overall very happy with the result, although it's a bit tough to justify the cost, in the end I would do it again. The DPMS stock tube removed all play and rattle, which I really appreciate. Call it a 5 star product for those that hate the SIG side folder, less if don't. Also, note that the DDLES adapter raises the cheek weld by .4 inches, so a riser is not needed or recommended.

Finally, if you don't like the SIG magazine that came with your 556 as most do, I found an additional use as a lower receiver bench vice block. You can use as is for light duty or remove the spring and follower, reinstall the floor plate, and fill with epoxy resin to strengthen.

Best,
=Mark=

http://www.brownells.com/.aspx/cid=7/Products/Rifle_Parts

 

[Zeus]

Nice post man :wink: This will be very usefull to a lot of folks on the board.

 

[derekm1988]

How solid?

Does the DDLES adapter make the folding buttstock rock solid? i'm not pleased with the play in my stock Classic. to me, not worth the $250 unless it has NO play in it.

 

[Mark]

Hey Zeus, thanks man!

Derek, it depends on your definition. I found the folding attachment point rock solid on the original stock and also on the DDLES adapter. What rattled on my 522 (and I assume the 556 Classic) was the stock itself. I am not a fan of the SIG side folder and absolutely hate the cheek weld.

I also have a 556 ER with an AR-type stock tube and that thing rattles as well! The new setup on the 522 is very tight, no rattles or play what so ever, but that is because of the DPMS commercial tube. The plastic tube that came with the ER is WAY out of spec, both in the shape and OD.

As a mod for the 556, I would say it's worth the money. It is rock solid and does have any play at all. As a mod for the 522, perhaps not such a good idea to spend $240 to replace the stock on a $400 machine. Just make sure to get a good tube and stock. Check these links.

http://www.brownells.com/.aspx/pid=26426/Product/COMMERCIAL_6_POSITION_CARBINE_STOCK_TUBE
http://www.brownells.com/.aspx/pid=23765/Product/CTR_BUTTSTOCK

Best,
=Mark=

 

[derekm1988]

556 mods

Thanks for the feedback. Always great to get others' perspective and experience.

 

[dtd80]

Awesome! Can't wait to get mine on. So many projects with not enough money and time.

 

[NavyDoc74656]

very useful post....i am planning on mounting my UBR onto my classic...

...bump...

 

[gstaylorg]

I recently replaced the Sig folder on two 556 SWATs using the DDLES adapter. It's very easy (as long as you have the right punches as suggested) even without any pics in the instructions (Hey I admit it...I look at the pictures, I DON'T read the articles (LOL)!!!).

In addition to cheekweld, I think there are some big advantages to going this route. First, you can use any buffer tube/castle nut/end plate you want. I went the the DPMS aluminum tube/nut and added a KZ end plate with a single point QD swivel sling adapter (fully ambidextrous, Botach Tactical).

Also, you can choose any stock you like, as long as it fits your buffer tube (mine are milspec). I went with Magpul MOEs, which are pretty reasonably priced.

Overall, this mod lightened up the weapon noticeably, and IMO improved the balance. So if you're willing to shell out the $$$ for the adapter, it's a very easy mod. Also, if you live in an area where a folder is a no-no, the DDLES adapter comes with an extra pin that will lock it in the extended (non-folded) configuration. At least with mine, they are rock solid...no play whatsoever. The only thing I noticed was that the first few times I pushed the release button to fold it, I had to actually push it in with a wooden dowel rod to get it to release. However, after just a few open/close runs, it works nice and smooth with a fingertip as designed.

Nice post Mark!

 

[Muad-dib]

Are those rear sling attachment points on your rifle? I am speaking of those black protrusions on both sides of the rifle just above where the stock pivot is.

 

[Schnibbs]

Overall, this mod lightened up the weapon noticeably, and IMO improved the balance. So if

How much is the difference in grams?
or rather: what is the weight of a Sig sidefolder and what is the weight of a complete stock set (consisting of adapter, buffer tube, end plate, nut and MOE stock)?

 

[gstaylorg]

I honestly can't tell you how many grams for specific items because I didn't weigh them before installation or after removal (I actually thought about doing this, but ended up being too lazy). Overall, adding the Quadrail (slight gain in weight), changing to MBUS sights, and changing from the Sig folder to the Magpul MOE/buffer tube decreased the weight between 1.0 to 1.5 lbs (~450-680 grams). So the overall weight of these rifles is 9.0 lb (~4.1 kg). Before modification, the weight was a little over 10.0 lb. I know that's more than what Sig advertises, but that's what I measured. My scale could easily be off, but the change in weight (before and after) is probably reasonably close. The weight fully loaded with a Nightforce 1-4x24 NXS optic and a full mag is 11.5 lb (~5.2 kg). Hope that helps.

 

[wired]

Mine....

 

[rookieshooter]

Great post!!! I just ordered my DDLES adapter a couple of days ago along with a CAA stock. I'm itching to put it on my Sig Swat. Hope it turns out as good as yours.

 

[rookieshooter]

Got my DDLES adapter today and it took me less than 5 minutes to put it on. The hardest part was convincing myself that I wouldn't damage my Sig while I pounded in that capturing roll pin they provided. Once I got over that fear, the rest was a piece of cake. Now, I'm waiting for my stock to get here and I'll be set.

Thanks everyone for your input.