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Daniel Defense Castle Nut Gun Model: AR-15, Condition: New, 56% Off, Blazin' Deal

Daniel Defense Castle Nut, 15-057-20039
Daniel Defense Castle Nut, 15-057-20039
Daniel Defense Castle Nut, 15-057-20039
Daniel Defense Castle Nut, 15-057-20039
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Daniel Defense Castle Nut, 15-057-20039
Daniel Defense Castle Nut, 15-057-20039
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Daniel Defense Castle Nut, 15-057-20039
Daniel Defense Castle Nut, 15-057-20039
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Daniel Defense Castle Nut, 15-057-20039

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Questions & Answers
does this work with the mk18 ris II rail? Expert Answer

The Daniel Defense Castle Nut will work with any AR15 platform rifle to secure either a Mil-spec, or Commercial spec buffer tube to your rifle. It is also compatible with DPMS and Armalite AR10 platform rifles.

by Ethan, Gear Expert, March 29, 2022
Is this a Steel Castle Nut? Expert Answer

Yes. The Daniel Defense Castle Nut is a 4140 tool steel castle nut with a heavy magnesium phosphate coating and is compatible with common armorers/castle nut wrenches.

by Ethan, Gear Expert, March 29, 2022
View All Q&A You Have a Question? Ask!
Customer Reviews
Helpful Positive Review
Daniel Defense Castle Nut by Joe, Verified Owner, October 5, 2024
The only castle nut I use. Daniel Defense quality and craftsmanship can’t be beat.
1/1 found this helpful
Helpful Positive Review
Daniel Defense Castle Nut by Sniper, July 9, 2019
A nice castle nut but color is way off for most lowers, end plates and buffer tubes I am familiar with. It is more gray/grey that black. The color might match well for Daniel Defense items if that is what you are looking for.
1/2 found this helpful
Helpful Positive Review
DD castle � by Koal, Verified Owner, March 29, 2021
Not all castle bits are of the same quality, there is a noticeable difference on the quality / durability of this DD castle nut. Not much else to say , not a part we think about that much, but quality all the way
1/1 found this helpful
Helpful Positive Review
Solid As Expected by Honeybadger, Verified Owner, April 22, 2021
Not all simple parts are made equal and this Daniel Defense one is beyond solid. It has crisp threads, shape edges, and is the real deal. I paired it with a Radian QD mount and everything is good to go. For around $8 this is a solid buy and I would r...
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1/1 found this helpful
Helpful Positive Review
Daniel Defense castle nut by Mac, May 2, 2019
This product was what I expected it to be. Daniel Defense products are the best of the best in my opinion. This product was purchased to replace a castle nut of lesser quality. My only gripe! When I placed the order, my payment was received and then ...
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2/3 found this helpful
Helpful Positive Review
its real milspec by Just Me, Verified Owner, April 6, 2020
There are lots of castle nuts on the market that advertise as milspec. The only thing milspec about many of them is the thread. The Daniel Defense castle nut is truly mil-spec. Correct outside diameter, width, and detent marks for staking.
1/2 found this helpful
Read All 28 Reviews

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Blazin' Deal
Prices have been cut drastically on this product as part of a special offer. These prices are so low that there's no double-dipping with coupons or any additional discounts, but you'll still get the best deal out there. This offer won't last long, so don't miss out!
Gun Model:
AR-15
Condition:
New

Code: DDD-CAN-CSTNT-15-057-20039

MPN: 15-057-20039

UPC: 815604018975

Blazin' Deal
List: $15.99Save 56%
$7.00
Purchase Restrictions Purchase Restrictions

Product Info for Daniel Defense Castle Nut

Get the Daniel Defense Castle Nut to secure your mil spec or commercial spec carbine receiver extension and rear receiver end plate to the lower receiver. These AR15 Lower Parts by Daniel Defense are finely crafted with recesses for staking your rear receiver end plate to prevent the castle nut from coming loose. Featuring a heavy magnesium phosphate coating, the Daniel Defense Securing Castle Nut is also compatible with common armorers and castle nut wrenches. The Daniel Defense Castle Nut Ring is a sturdy and affordable way for you to secure your receiver extension to ensure maximum durability.image

Specifications for Daniel Defense Castle Nut:

Manufacturer: Daniel Defense
Gun Model: AR-15
Condition: New

Package Contents:

  • Daniel Defense Castle Nut, DDD-CAN-CSTNT

Daniel Defense Castle Nut Orderable Models

List of Orderable Models

  • Daniel Defense Castle Nut, 15-057-20039 , MPN: 15-057-20039 , UPC: 815604018975 , Code: DDD-CAN-CSTNT-15-057-20039
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Last updated 2026-09-15 UTC.