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Reviews & Ratings for Stern Defense SD BU9 9mm Bolt Carrier for AR-15 Glock-Pattern Upper Receiver — 7 reviews

(7 reviews)
Stern Defense SD BU9 9mm Bolt Carrier for AR-15 Glock-Pattern Upper Receiver
Stern Defense SD BU9 9mm Bolt Carrier for AR-15 Glock-Pattern Upper Receiver
$181.20 $129.99 Save 28%
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Most Helpful Positive Review HAS NOT FAILED ONCE
This was is my first AR9 build and I wanted to use my Glock mags on it so I order the Stern Defense 9mm conversion and I paired it with the Stern Defense bolt carrier and I can’t be more pleased. Been to the range a few times to set a few things and I have not had any issue with it.
Most Helpful Negative Review Does not work with echo sport trigger
I already had a 9mm bolt but as with most as far as the echo sport trigger the hammer slot is to naefor the hammer lock. So instead of modifying the bolt I had I decided to get the stern defense bolt, I plan on building another 9mm anyway. Stearns bolt says it works with the echo sport trigger but a...
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AR-9 Build

by Pete P., Verified Owner from SD, United States Written on November 25, 2025
I had an AR-9 upper and wanted to finish my build (for an M&P type). I had no issues with this dropping in and cycling with the PSA upper, the Anderson lower wearing a Stern magwell adapter.
Pros:
  • Solid well built
  • Cost & availability
Cons:
  • None
Would recommend: Yes
Was it helpful to you? Yes | No
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Bolt is a Gem

by MLEW, Verified Owner from PA, United States Written on August 1, 2025
Works flawlessly with Fostech Echo Binary Trigger! Fit and finish are excellent!
Would recommend: Yes
Was it helpful to you? Yes | No
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Stern Defense SD BU9 bolt carrier

by weldr123, Verified Owner from AL, United States Written on May 21, 2025
I purchased this bolt carrier and paired it with a Stern Defense MAG-AD9 AR-15 Glock 9mm/.40 Magazine Conversion Adapter. I just didn't like the Colt magazines or the Colt style conversion block. I am 100% satisfied with my purchase and would buy it again.
Pros:
  • plug and play
Cons:
  • None
Would recommend: Yes
Was it helpful to you? Yes | No
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Stern Defense SD BU9 bolt carrier

by weldr123, Verified Owner from AL, United States Written on May 21, 2025
I purchased this bolt carrier and paired it with a Stern Defense MAG-AD9 AR-15 Glock 9mm/.40 Magazine Conversion Adapter. I just didn't like the Colt magazines or the Colt style conversion block. I am 100% satisfied with my purchase and would buy it again.
Pros:
  • plug and play
Cons:
  • None
Would recommend: Yes
Was it helpful to you? Yes | No
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Good products

by Joey, from ID, United States Written on March 7, 2024
I m doing an ar9 build and needed a bcg for it . My friend suggested optics planet . I purchased a stem defense SD bu9 . I haven’t shot mine yet but I did try my friend’s it fired flawlessly that’s why I decided to purchase it. Seems to be high quality and a fair price.
Would recommend: Yes
Was it helpful to you? Yes | No
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