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Questions & Answers
gas system length?

It states in the product description it has a rifle length gas system

by Jeff Johnson, Verified Owner, February 27, 2022
Customer Reviews
Most Recent Reviews
Owner/shooter by Johnny, July 2, 2026
So far I am very pleased with this upper. The accuracy has met all my expectations, after a site in and barrel break in shooting darn close to moa.
Read 1 Review
Caliber:
5.56x45mm NATO
Overall Length:
27 in
Barrel Length:
18 in
Barrel Profile:
Government
Gas System Length:
Rifle Length
Barrel Twist Rate:
1-9
Firearms Threads Per Inch:
1/2x28
Handguard Type:
Free-Float
Muzzle Device:
A2 Flash Hider
Finish:
Anodized
Color:
Black
Gun Model:
AR-15
Gas Block Journal Size-Diameter:
.750 in
Handguard Length:
15 in
Barrel Material:
416R Stainless Steel
Weight:
8 lb

Code: 3FN-UFH-AR1518M12-BAA3-M12

MPN: BAA3-M12

UPC: 812058030188

List: $459.95Save $27.60
$432.35

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made-in-usa-flag Made in USA

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 Luth-AR 5.56 Mark 12 Complete Upper Barrel Receiver Assembly

Starts with Luth-AR 18in, 5.56mm Lightweight barrel made from 4150 Chrome Molly with a 1-9 twist mated to Luth-AR A3 Flattop receiver which includes bolt carrier, charging handle, forward assist and ejection port cover. The upper is then topped off with Luth-AR Lo-profile gas system and ergonomic 15in Palm Handguard with KeyMod slots and a Picatinny top-rail.image

Specifications for Luth-AR 5.56 Mark 12 Complete Upper Barrel Receiver Assembly:

Manufacturer: Luth-AR
Caliber: 5.56x45mm NATO
Overall Length: 27 in
Barrel Length: 18 in
Barrel Profile: Government
Gas System Length: Rifle Length
Barrel Twist Rate: 1-9
Firearms Threads Per Inch: 1/2x28
Handguard Type: Free-Float
Muzzle Device: A2 Flash Hider
Finish: Anodized
Color: Black
Gun Model: AR-15
Fabric/Material: 4140 Chrome Moly
Gas Block Journal Size-Diameter: .750 in
Handguard Length: 15 in
Handguard Style: Round Rail
Gun Rail: KeyMod
Gun Make: AR Platform
Barrel Material: 416R Stainless Steel
Weight: 8 lb
Bolt Carrier Group Included: MIL-SPEC
Charging Handle Included: MIL-SPEC
Magazine Included: No
Country of Origin: USA

Features of Luth-AR AR-15 MARK12 Complete Upper Barrel Receiver Assembly

  • 18 inch Mark12 Barrel
  • 5.56 mm
  • 4140 Chrome Moly
  • Threaded Barrel - Thread Pitch 1/2 x 28
  • 1-9 RH Barrel Twist
  • 6 Lands and Groves
  • M4 Feed Ramp
  • Button Broached

Package Contents:

  • Luth-AR 5.56 Mark 12 Complete Upper Barrel Receiver Assembly

Luth-AR 5.56 Mark 12 Complete Upper Barrel Receiver Assembly Orderable Models

List of Orderable Models

  • Luth-AR Mark 12 Complete Upper Barrel Receiver Assembly, 5.56 mm, 27in, 18in, Government, Rifle, 1x9, 1/2x28, Picatinny,Key MOD, A2 Flash Hider, Anodized, Manganese Phosphate, Black, BAA3-M12 , MPN: BAA3-M12 , UPC: 812058030188 , Code: 3FN-UFH-AR1518M12-BAA3-M12
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Last updated 2026-07-03 UTC.