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Stag Arms AR-15 A3 Flattop Upper Receiver Up to $10.00 Off w/ Free Shipping — 3 models

Stag Arms AR-15 A3 Flattop Upper Receiver, Stripped, Direct Impingement, Type 3 Hard Coat Anodized, Left Hand, Black, STAG310264
Stag Arms AR-15 A3 Flattop Upper Receiver Assembly, Direct Impingement, Type 3 Hard Coat Anodized, Right Hand, Black, STAG300412
Stag Arms AR-15 A3 Flattop Upper Receiver Assembly, Direct Impingement, Left Hand, Cerakote, FDE, STAG310864
Stag Arms AR-15 A3 Flattop Upper Receiver, Stripped, Direct Impingement, Type 3 Hard Coat Anodized, Left Hand, Black, STAG310264
Stag Arms AR-15 A3 Flattop Upper Receiver Assembly, Direct Impingement, Left Hand, Cerakote, FDE, STAG310864
Stag Arms AR-15 A3 Flattop Upper Receiver, Stripped, Direct Impingement, Type 3 Hard Coat Anodized, Left Hand, Black, STAG310264
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Stag Arms AR-15 A3 Flattop Upper Receiver, Stripped, Direct Impingement, Type 3 Hard Coat Anodized, Left Hand, Black, STAG310264
Stag Arms AR-15 A3 Flattop Upper Receiver Assembly, Direct Impingement, Type 3 Hard Coat Anodized, Right Hand, Black, STAG300412
2 of 5 images
Stag Arms AR-15 A3 Flattop Upper Receiver Assembly, Direct Impingement, Type 3 Hard Coat Anodized, Right Hand, Black, STAG300412
Stag Arms AR-15 A3 Flattop Upper Receiver Assembly, Direct Impingement, Left Hand, Cerakote, FDE, STAG310864
3 of 5 images
Stag Arms AR-15 A3 Flattop Upper Receiver Assembly, Direct Impingement, Left Hand, Cerakote, FDE, STAG310864
Stag Arms AR-15 A3 Flattop Upper Receiver, Stripped, Direct Impingement, Type 3 Hard Coat Anodized, Left Hand, Black, STAG310264
4 of 5 images
Stag Arms AR-15 A3 Flattop Upper Receiver, Stripped, Direct Impingement, Type 3 Hard Coat Anodized, Left Hand, Black, STAG310264
Stag Arms AR-15 A3 Flattop Upper Receiver Assembly, Direct Impingement, Left Hand, Cerakote, FDE, STAG310864
5 of 5 images
Stag Arms AR-15 A3 Flattop Upper Receiver Assembly, Direct Impingement, Left Hand, Cerakote, FDE, STAG310864

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Questions & Answers
I built a Palmetto kit for my lower and the upper was already built. Can I replace the upper that I have with this and just use that barrel etc? Expert Answer

Yes. You should not have an issue doing so as this was designed to fit Mil-Spec AR15 lowers. Keep in mind this is a left handed upper and will require a left handed BCG or bolt.

by Ethan, Gear Expert, January 20, 2022
See 1 More Answer
Is the aluminum 6061 or 7075? Expert Answer

Stag Arms only states that the Stag Arms 15 A3 .300 AAC Blackout Upper Receiver Assembly is Forged and mil-spec with type 3 hard coat anodizing and a picatinny rail on top. I'd recommend reaching out to the manufacturer for more information.

by Ethan, Gear Expert, February 28, 2022
View All Q&A You Have a Question? Ask!
Customer Reviews
Helpful Positive Review
best forged lefty upper on the market by Danimal, Verified Owner, June 6, 2026
I have four of these. The fit and finish is perfect. The machining and measurements are very precise with no wiggle on multiple different lowers. The 7075 aluminum is much tougher than other 6061 slick side uppers on the market made by KAK, KMT, WMD ...
Read More...
1/1 found this helpful
Helpful Positive Review
Coincidence? by Simonsay629, Verified Owner, August 13, 2021
Arrived on my front door step on National Left Hand Day. Today!!! Coincidence? Cant wait to put this together and test. Finally. No more burnt biceps. Looks like well built, good quality. Fast shipping.
3/4 found this helpful
Helpful Positive Review
Stag Arms Left Hand Upper by Max, Verified Owner, November 16, 2021
My first experience with Stag. The upper is well made and no complaints. I do see that I will have to modify/shorten the ejection port cover rod to make the upper work with a rail that has anti-rotation that extends on the upper’s sides. Other than t...
Read More...
2/2 found this helpful
Helpful Positive Review
Best and really only option for left handed ARs by Bryan Verduzco, Verified Owner, July 8, 2020
this is my second stag left handed upper that I have purchased. Both have been well made and high quality, this one is no exception. I was able to put my rifle together with no issues and this thing is holding up just fine.
10/10 found this helpful
Most Recent Reviews
Too much of a hassle by Olowrin, Verified Owner, November 18, 2023
I'm left handed. If you buy this, you will need to also have left handed everything. The BCG must be a left handed one (only made by Stag). The free-float rail also will not fit this since the ejection port opens from the top. I couldn't get it to fi...
Read More...
0/5 found this helpful
Most Recent Reviews
Stag upper reciever by Ncoutlaw, Verified Owner, November 6, 2025
Part is top notch. great quality and attention to detail.
Read All 13 Reviews
3 Models Available
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ATTENTION! We currently do not ship this product to P.O. Boxes, AK, CA, CT, DE, HI, MA, NJ, NY, U.S. Territories, or select Colorado locations. Please see our policies for more information or a detailed list of locations.

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Help support American manufacturing! Marked models of this product have gone through rigorous review and been certified by the manufacturer as Made in the USA.

Product Info for Stag Arms AR-15 A3 Flattop Upper Receiver

The A3 upper receiver assembly is made to mil-spec standards and includes a picatinny rail on the top, dust cover, and installed forward assist.image

WARNING: California`s Proposition 65

Specifications for Stag Arms AR-15 A3 Flattop Upper Receiver:

Manufacturer: Stag Arms
Fabric/Material: Aluminum
Gun Make: AR Platform
Gun Model: AR-15
Condition: New
Country of Origin: USA

Features of Stag Arms 15 A3 Upper Receiver Assembly:

  • Pivot/Takedown Pin Size: Small pin - .250"
  • Material: Forged and mil-spec with type 3 hard coat anodizing and a picatinny rail on top

Package Contents:

  • Stag Arms AR-15 A3 Flattop Upper Receiver

What firearm models does the manufacturer say Stag Arms AR-15 A3 Flattop Upper Receiver is compatible with?

The manufacturer suggests that Stag Arms AR-15 A3 Flattop Upper Receiver is compatible with AR-15

Stag Arms AR-15 A3 Flattop Upper Receiver Orderable Models

List of Orderable Models

  • Stag Arms AR-15 A3 Flattop Upper Receiver, Stripped, Direct Impingement, Type 3 Hard Coat Anodized, Left Hand, Black, STAG310264 , MPN: STAG310264 , UPC: 840213903299 , Code: 2PS-UPR-AR15A3FURA-STAG310264
  • Stag Arms AR-15 A3 Flattop Upper Receiver Assembly, Direct Impingement, Type 3 Hard Coat Anodized, Right Hand, Black, STAG300412 , MPN: STAG300412 , UPC: 811546026719 , Code: 2PS-UPR-AR15A3FURA-STAG300412
  • Stag Arms AR-15 A3 Flattop Upper Receiver Assembly, Direct Impingement, Left Hand, Cerakote, FDE, STAG310864 , MPN: STAG310864 , UPC: 840213903336 , Code: 2PS-UPR-AR15A3FURA-STAG310864

Stag Arms AR-15 A3 Flattop Upper Receiver Unavailable & Discontinued Models

List of Unorderable Models

  • USED Stag Arms AR-15 A3 Flattop Upper Receiver, Assembly, Direct Impingement, Type 3 Hard Coat Anodized, Left Hand, Black, STAG310412, EDEMO7, Used, Condition Fair , MPN: STAG310412-EDEMO7 , Code: 2PS-UPR-AR15A3FURA-STAG310412-EDEMO7
  • USED Stag Arms AR-15 A3 Flattop Upper Receiver Assembly, .250 Small Pin, Left Hand, Type 3 Hard Coat Anodized, Picatinny Rail, Black, STAG310412, EDEMO6, Condition Fair, Used , MPN: STAG310412-EDEMO6 , Code: 2PS-UPR-AR15A3FURA-STAG310412-EDEMO-US-D
  • USED Stag Arms AR-15 A3 Flattop Upper Receiver, Assembly, Direct Impingement, Type 3 Hard Coat Anodized, Left Hand, Black, STAG310412, EDEMO9, Condition Fair, Other , MPN: STAG310412-EDEMO9 , Code: 2PS-UPR-AR15A3FURA-STAG310412-EDEMO-OT-D
  • USED Stag Arms AR-15 A3 Flattop Upper Receiver, Assembly, Direct Impingement, Type 3 Hard Coat Anodized, Left Hand, Black, STAG310412, EDEMO8, Used, Condition Fair , MPN: STAG310412-EDEMO8 , Code: 2PS-UPR-AR15A3FURA-STAG310412-EDEMO8
  • Stag Arms AR-15 A3 Flattop Upper Receiver, Assembly, Direct Impingement, Type 3 Hard Coat Anodized, Left Hand, Black, STAG310412 , MPN: STAG310412 , UPC: 811546026955 , Code: 2PS-UPR-AR15A3FURA-STAG310412
  • Stag Arms AR-15 A3 Flattop Upper Receiver Assembly, Direct Impingement, Right Hand, Cerakote, FDE, STAG300864 , MPN: STAG300864 , UPC: 840213903329 , Code: 2PS-UPR-AR15A3FURA-STAG300864
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Last updated 2026-07-07 UTC.