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SIG SAUER MCX/MPX Side-Folding M4 Style Stock Black - All NFA Rules Apply STKXFOLDM4BLK
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Most Helpful Positive Review M4 stock for MPX
Great M4 style stock to replace the retractable stock that came with the MPX Carbine making it feel more familiar. Easy to install and adjust. The folding capability is nice. Been using it in USPSA competitions and it feels very sturdy. Great price and service from Optics Planet.
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Great quality

by Average shooter, Verified Owner from NC, United States Written on December 11, 2024
I purchased this to add a buffer tube and pistol brace to my SIG MCX. The stock that ships with it is really nice and I will likely use it on another rifle. That hinge mechanism is great quality and very smooth.
Pros:
  • Quality construction
Cons:
  • None
Best Used for:
  • Adding buffer tube to buffer less rifle
Would recommend: Yes
Was it helpful to you? Yes | No

Awesome stock

by Nick, Verified Owner from AZ, United States Written on August 23, 2024
I have purchased 2 of these stocks. These are great products bought one for my spear and one for my PCC. Strong and sturdy holds up very well looks great and feels comfortable when shooting. I would recommend getting one.
Would recommend: Yes
Was it helpful to you? Yes | No

Just what ineeded.

by David Garcia, Verified Owner from CO, United States Written on July 6, 2024
I got this to upgrade the Magpul MOE SL-K on my MCX. I wanted something a little more substantial. I like the extra purchase on my shoulder and I like the OEM aesthetic. Super pleased. Best price anywhere, to boot.
Would recommend: Yes
Was it helpful to you? Yes | No

solid product

by Rob, Verified Owner from CO, United States Written on May 5, 2024
The stock mounts firm to the rail and is smooth transitioning between folded and unfolded.
Pros:
  • great max extension
  • check weld placement
  • folding lock mechanism
Cons:
  • None as of yet
Best Used for:
  • Piston driven, supressed or slick side ARs
Would recommend: Yes
Was it helpful to you? Yes | No

Nice solid pic-mount folding stock

by BenM, Verified Owner from OR, United States Written on April 27, 2024
Got this to replace the non-adjustable stock that came on my JAKL. The folding mechanism was pretty well stuck at first but I eventually got it loose and folding. The stock mounted easily and it looks great, plus now I have an adjustable length-of-pull. It locks up tight, with no wobble.
Would recommend: Yes
1 of 1 found the following review helpful.
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Sick Sig Folding/Sliding Stock

by William Nimis, Verified Owner from FL, United States Written on February 19, 2024
Going to throw this on my B&T APC10 pro as soon as my stamp comes in. Stock telescopes perfectly and folds easily, and it is just a great stock, especially for the price.
Would recommend: Yes
Was it helpful to you? Yes | No

Very nice quality, fits perfect.

by Shoe, from VA, United States Written on January 8, 2024
I was afraid this Sig stock would be too bulky but fits my MPX perfectly and makes it a more comfortable gun to shoot. The closing latch is stiff and a little difficult to close but I’m hoping it will ease up with use. For me it’s an improvement over the skeletonized stock.
Pros:
  • Comfortable
  • Comforatble
Cons:
  • A little difficult to fold
Would recommend: Yes
1 of 1 found the following review helpful.
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good deal f

by Benny, Verified Owner from CA, United States Written on December 16, 2023
Easy to install, fits perfect, fast delivery, great price, but no instruction on how to fold the buttstock, still looks good even without folding stock, handles great when firing weapon, can transport it in my weapons case without breaking it down
Would recommend: Yes
Was it helpful to you? Yes | No

SIG Sauer virtus

by dieseltruckstuff, Verified Owner from MI, United States Written on August 10, 2023
What a great product, changes the entire platform. Would recommend. This improves the versitility of the rifle and makes it your go to weapon. SIG Sauer has quality products and optics plant makes it easy to obtain them.
Pros:
  • ease of entall
Cons:
  • pricy
Best Used for:
  • Go to rifle
Would recommend: Yes
0 of 1 found the following review helpful.
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Great Folding Stock

by Scotty, from WA, United States Written on August 6, 2020
Purchased the Sig MCX folding stock for my Ruger PC9 (gen 3). Stock fit and finish is good and it fit the rifle very well. While having a folding stock is a matter of personal taste, I am very pleased with the way the rifle can be taken down and fit comfortably in a back pack. I would recommend the folding stock to shooters looking for ways to enhance the looks and carry profile of their weapon.
Pros:
  • Minimizes carry length of your rifle. Looks wicked.
Cons:
  • Price is steep.
Best Used for:
  • Concealment and carry profile.
Would recommend: Yes
1 of 1 found the following review helpful.
Was it helpful to you? Yes | No
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Last updated 2025-11-12 UTC.