Kimberkid, that stock set up on the P556 looks great!

A few years ago there was a forum member who took a batch of factory 55X gas valves and drilled them to one of a couple specs, including a suppressed setting. I had two of his modified gas valves but sold one.

I seem to recall that one of the SAN SIG importers, maybe COG or JDI, was selling some factory 3 and 4 position gas valves (including a suppressed setting) several years ago.

Modern Day Savage ... I think that's the one I got but it only fit my 553, the piston on the 556 is larger and wouldn't fit ... my 553 isn't a safe queen but the 556 is what I shoot the most.

quote:

Originally posted by kimberkid:
Modern Day Savage ... I think that's the one I got but it only fit my 553, the piston on the 556 is larger and wouldn't fit ... my 553 isn't a safe queen but the 556 is what I shoot the most.

Member SigMadMan offered his 55X modified gas valves in both the 553 and 556 diameter piston sizes, and also gave the option of purchasing one of his or sending your gas valve to him to be modified. Wanting the option to keep my factory gas valves in original condition I chose to purchase his modified ones in both piston sizes.

P556 original gas valve on left and modified gas valve on right.







Modified 556 gas valve

Does your adapter lock in tightly? The one I tried in my 553 wigglesa bit. I'll have to try a 556 lower

quote:

Originally posted by Modern Day Savage:
Member SigMadMan offered his 55X modified gas valves in both the 553 and 556 diameter piston sizes, and also gave the option of purchasing one of his or sending your gas valve to him to be modified. Wanting the option to keep my factory gas valves in original condition I chose to purchase his modified ones in both piston sizes.

Thanks, I didn't remember who I got it from! I'll try and contact him to to see if he has any more ... I like to keep my original parts too.

quote:

Originally posted by PGT:
Does your adapter lock in tightly? The one I tried in my 553 wigglesa bit. I'll have to try a 556 lower

Although mine is a early pistol I have a 556Xi lower (because I wanted the solid trigger guard, ambidextrioys mag release ... and the logo on the magwell) but it has a bit of wiggle in it too, my original solid pin was too big to fit in the adapter and I had to get a generic roll pin from the hardware store, so I guess I'll make a shim or something as that really bugs me ... Besides, as Cooper and other old gun experts have said (back when I used to read the SGN), a gun that is loose in the stock will never be accurate ... and the accuracy of mine has gone from sub 1.5" @ 100 to 4-6" MOA @ 100

quote:

Originally posted by PGT:
Does your adapter lock in tightly? The one I tried in my 553 wigglesa bit. I'll have to try a 556 lower

Follow-Up!

My adapter has a threaded hole (8x1.25mm) at the bottom that I was going to just get a set screw for ... but it needs to be about 1.25" long so I found a cap-screw and one was a tad short and the next length a bit too long. So I cut a piece of .5" thick derlin(sp?) plastic I had laying around and cut a notch for the latch, then found a set screw that's about 9/16" long that will tighten it up ... the plastic will disperse the pressure of the screw but still have to be careful not to over torque it and break the catch on the lower!

Google is your friend;
Google is your friend

Dam it ...

I googled so may terms and I'd swear one of them had a few 556's in them but of course they were also littered with the MPX and MCX ... I may have also seen something shiny and gotten confused too
... my bad

I did notice the Kate Moss fold to the right, so it wouldn't interfere with the charge handle as its on the other side.

The collapsible MPX stock covers just a bit of the charge handle slot on mine ... I tested it by unlocking the charge handle and firing a round, the stock slid back about 3" so I so I didn't try it with the stock locked in the collapsed position. The second position is fine tho

quote:

Originally posted by kimberkid:
Josh, I didn't try that on Wednesday but last night I put a SWAT hand-guard on it and had it in the back of the truck to run out to the farm on my lunch hour ...

A bit better? picture

kimberkid - How satisfied are you with this telescoping stock on your 556? I purchased the adapter referenced in the thread primarily because it was still available, but haven't purchased the stock yet. I also have a ACR folding stock adapter for my 556, but I'm on the fence about the SIG telescoping stock, which seems REALLY cool as well!

Any feedback you can share would be much appreciated. Also what is the LOP with the stock fully extended? That might help in my decision as well... Thx.

quote:

Originally posted by nhracecraft:
kimberkid - How satisfied are you with this telescoping stock on your 556? I purchased the adapter referenced in the thread primarily because it was still available, but haven't purchased the stock yet. I also have a ACR folding stock adapter for my 556, but I'm on the fence about the SIG telescoping stock, which seems REALLY cool as well!

Any feedback you can share would be much appreciated. Also what is the LOP with the stock fully extended? That might help in my decision as well... Thx.

nhracecraft ... well, just to clear up any misconception, it is cool! AND it’s more comfortable than any wire or collapsible stock I've ever shot; Daewoo AR110C, HK93, VZ58, AK AMD65 are the ones I’ve owned and have firsthand experience with … and the other best thing about it is that unlike most folding stocks, like the SiG and ACR, it doesn't make the rifle noticeably wider.
BTW I like the SiG factory stock but I am also a huge fan of the ACR stock, not only on my ACR but I also bought an adapter from “the lucky Irishman” but it was for my CZ Bren 805 SBR’d pistol.

I really think if SiG had released the 556Xi line with this or a similar collapsing stock it would have been a huge success. I would like to be able to adjust the stock down another notch or two but the design of the 556 receiver won’t accommodate it … with this stock I can put it behind the back seat of my truck and someone can sit there and not even notice it, no so with the original folding stock … its too bulky.

While I was measuring it I took some new pictures, as I understand it the LOP is measured from the trigger to the stock (about 12") but just in case I included a picture from the front of the receiver to the end of the extended stock(17.5") or by doing a little math you can get approximate any measurement you need.

I'm about 5'6" and it fits me just right for the eye relief with my ACOG; but I wouldn't want it any shorter either. I'm using the MPX stock, you shouldn't shoot it with the stock completely closed as the MPX stock is in line with the charging handle while cycling/ejecting

If you needed a bit more length you could get the MCX ... If you do have any other questions just ask or email me!

BTW ... if anyone knows of a 4 position gas valve for using a suppressor, info or a link would be greatly appreciated!

What adapter do you need to do this. Very cool looking stock.

Thank you so much. Knew this thread was a little old never expected such a quick response. Had my 556 just waiting for stalk adapters remember seeing discussions about it for the ACR and seemed like nothing ever happened. My 556 is one of the original 1st versions of the factory SBR they did, that’s how long I have been waiting. It’s one of the first of only 500 they were going to make, but hen guess they were popular and they made more which I wasn’t to upset (good for anyone else that wanted them. Then the pistol brace came out (good on SIG) and that was a game changer and then I was like crap wished I waited for those a lot cheaper lol. All good at least now you helped me finally get what this post was all about. Awesome truly appreciated. I was so happy to see the adapters I bought one for the ACR stock too.

Thanks Black92LX, this is the first time I've seen this come up in my notifications ... I found this adapter when CDNN was blowing them out for something like $19.95 and it came in SiG packaging, otherwise I'd have never known how much I like it. I do wish I'd have ordered the longer MCX stock, which is no longer available, now they only make the shorter MPX stock.

You can get third party rods in just about any length you need.

Glad to hear that the collapsing stocks/ braces function well and look great on the platform. You guys inspired me to order the pic rail adapter and SB MCX brace for the original m4 lower style on my inbound 556 pistol.

quote:

Originally posted by hrcjon:
You can get third party rods in just about any length you need.

I hadn't even looked until now, found some at Title II Arms for $79
Thanks for that ...

quote:

Originally posted by hrcjon:
You can get third party rods in just about any length you need.

Gotta link for the 'Mod Rods'?

I got my "rods" here...http://www.titleiiarms.com/SIG_Telescoping_RODS.html
by now there are probably other sources as well.

Got the MPX brace and KNS pic adapter inbound. Really digging pistols that don’t need buffer tubes and have non-AR charging handle locations.



Pics of builds in progress: BRN-180, P556, Extar super light weight pistol:

https://ibb.co/1rpCjMn