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Questions & Answers
Are one of these two models the adapter WITH the flange? If so, which is which? Please update your product listing to clarify Expert Answer

Yes, the model 3GL-STA-KNSPIC-AR-MCX-ADAP-W-FLANGE include the Flange. If you look at the MPN for the item, it indicates "AR/MCX Adap w/ Flange" to confirm that unit comes with it.

by Tiffany S., Gear Expert, August 15, 2019
Could I use this with a sig 516 upper on a mill spec lower and what’s the flange no flange option Expert Answer

The KNS Precision AR15 Buffer to Picatinny Rail Adapter Kit will not work with a Sig 516 since that rifle uses a buffer assembly.

by Hunter, Gear Expert, October 10, 2022
Customer Reviews
Helpful Positive Review
perfect from my 22lr AR build by Joe, Verified Owner, April 28, 2022
Works perfect and does not allow the bcg to move. I installed on my 22lr build for more pistol look and will attach a folding stock later on. Took to the range and runs flawlessly. Could not ask for a better product.
3/4 found this helpful
Helpful Positive Review
Great adapter by Aaron., Verified Owner, August 6, 2024
Does exactly what it is supposed to do, works great for my brn 180 upper.
1/1 found this helpful
Helpful Positive Review
good for what it is by Dave Winters, Verified Owner, October 14, 2021
It’s easy enough to install onto a standard lower. The flange version stops the real takedown pin from coming out. I used it to install a sig folding stock on a 22lr dedicated upper. This parts kit worked perfect with the sig 1919 adapter.
1/2 found this helpful
Helpful Positive Review
Perfect for what I was looking for. by Phoenix, September 23, 2020
Works exactly as described. Expected nothing less. It attaches to the back end of a pistol for a folding brace to be able to be attached. I had one of those laying around and this helped me save money so I didn’t need to buy another type of brace.
2/3 found this helpful
Most Recent Reviews
picatinny adapter by ARD, Verified Owner, September 6, 2025
Fits real nice an tight I like the look can’t wait to finish the build
Most Recent Reviews
Does not work with the Sig Rattler by Klugey1, Verified Owner, November 13, 2022
The MCX Sig Rattler requires the bolt and piston system to retract about 3/4” into the back of the lower receiver (into back edge of the buffer tube threading). This KNS product screws into the buffer tube threading so that it is flush with the FRONT...
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0/4 found this helpful
Read All 6 Reviews
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Product Info for KNS Precision AR15 Buffer to Picatinny Rail Adapter Kit

The KNS Precision AR/MCX Stock Adapter allows the user to mount a picatinny-style stock attachment (such as the Sig MPX folding stock or brace) in place of an AR15-style buffer tube. Many firearms utilize the buffer tube attachment of the AR15 in order to mount common stocks & braces, but do not mechanically require the tube for in-line buffer spring. For these weapons, this KNS Precision AR/MCX Stock Adapter offers a modular alternative for attaching stocks or other accessories. The KNS Precision AR/MCX Stock Adapter kit is composed of two parts and an attaching bolt. The externally-threaded adapter plug of the KNS Precision AR/MCX Stock Adapter kit fits into the threaded buffer socket or ring. The adapter rail section of the KNS Precision AR/MCX Stock Picatinny Rail Adapter kit fits into the slot in the adapter plug and is secured to the firearm and the adapter rail by a hex-socket bolt and lock washer.image

Specifications for KNS Precision AR15 Buffer to Picatinny Rail Adapter Kit:

Manufacturer: KNS Precision
Condition: New
Color: Black
Gun Make: AR Platform
Gun Model: SIG Sauer MCX, AR-15
Fabric/Material: Aluminum
Attachment Type: Picatinny
Mount Type: Picatinny

Package Contents:

  • KNS Precision AR15 Buffer to Picatinny Rail Adapter Kit

KNS Precision AR15 Buffer to Picatinny Rail Adapter Kit Orderable Models

List of Orderable Models

  • KNS Precision AR15 Buffer to Picatinny Rail Adapter Kit with Flange, Black, AR/MCX Adap w/ Flange , MPN: AR/MCX Adap w/ Flange , UPC: 853906008492 , Code: 3GL-STA-KNSPIC-ADAP-W-FLANGE
  • KNS Precision AR15 Buffer to Picatinny Rail Adapter Kit without Flange, Black, AR/MCX Adapter w/o Flange , MPN: AR/MCX Adapter w/o Flange , UPC: 853906008430 , Code: 3GL-STA-KNSPIC-ADAP-W-O-FLANGE

KNS Precision AR15 Buffer to Picatinny Rail Adapter Kit Unavailable & Discontinued Models

List of Unorderable Models

  • USED, KNS Precision AR15 Buffer to Picatinny Rail Adapter Kit without Flange, Black, AR/MCX Adapter w/o Flange , MPN: AR/MCX Adapter w/o Flange-EDEMO , Code: 3GL-STA-KNSPIC-ADAP-W-O-FLANGE-EDEMO-RE-C
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