Sylvan Arms

Premium Quality and Affordability


Custom AR9 Bolt Extension .531

(1 customer review)


Availability: In stock (can be backordered)

SKU: RBE-531 Categories: ,

The Custom AR9 Bolt Extension is for our Folding Stock Adapter customers that have a smaller diameter BCG. The Bolt Extension diameter is .531, commonly used to fit FX9 and other AR9 builds that have a smaller diameter bolt carrier group. To ensure proper fitment, please measure the inside diameter of your BCG. Not all AR9’s require a smaller bolt extension and can work with the standard .625 bolt extension that comes with our Folding Stock Adapter.

Will not fit Gen 4 Folder

Product Details

  • Weight: 2.925 oz.
  • Diameter: .531 in.
  • Most commonly needed for FX-9’s

If you have any questions, please contact us before ordering.


1 review for Custom AR9 Bolt Extension .531

  1. Nicholas Hernandez

    I needed this to fit my AR-9 bolt by JP Enterprises, worked like a charm.

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