Your basket is empty.

Basket

Help and contact

Free standard delivery over £199

100-day return policy

Newsletter

Sale

Over 300,000 customers - we say thank you!

4.93/5 "Very good" (1400+ reviews)

40,000+ products for hunting and shooting sports

The Brownells A1 20" rifle barrel features a lightweight design, chrome-lined bore, 1-12" twist, and is perfect for Retro Rifle™ builds or AR-15s.

BROWNELLS BRN AR-15/A1 5.56MM 20" 1-12 TWIST RIFLE BARREL ASSEMBLY

050806029460 100020999

Restrictions

Is a 'Call to order' product.

Top takeaways

The Brownells Retro A1 20" rifle barrel is designed to replicate the original M16A1 "skinny" barrel, ideal for Retro Rifle™ builds or any lightweight AR-15 setup.
Chambered in 5.56x45, it features a 1-12" twist, chrome-lined bore, and matte black phosphate finish, with a ½"-28 tpi muzzle thread and pre-installed standard rifle barrel extension.
Constructed from 4150 chrome-moly steel, the barrel is magnetic particle inspected to ensure quality and durability, and requires a separate rifle-length gas tube.

Attributes

Cartridge:
```
5.56 mm NATO
```
Finish:
```
Black
```
Gas System Length:
```
Rifle
```
Length:
```
20''
```
Muzzle Threads:
```
1/2-28
```
Twist:
```
1-12
```
Weapon type:
```
AR-15
```
Delivery weight: 1.043kg
Shipping height: 25mm
Shipping width: 152mm
Shipping length: 523mm
UPC: 050806029460

Item details

Made in USA
US export classification: 0A501.c

Specifications:
Cartridge: 5.56 mm NATO
Finish: Black
Gas System Length: Rifle
Length: 20''
Make: AR-15
Muzzle Threads: 1/2-28
Twist: 1-12

279.9 279.9 1 GBP

279.9 GBP £279.90

Prices inclusive of duty & VAT.

Product no.: 100020999

Mfr. No.: BABR5512999M

050806029460 The Brownells Retro A1 rifle length barrel replicates exactly the exterior contours of the original "skinny" barrel of the M16A1 rifle, so it's ideal for building your own Retro Rifle™ OR any AR-15 where a lightweight barrel is desirable. Chambered in 5.56x45, this chrome-lined barrel has a 1-12" twist and is finished in matte black phosphate, with an overall length of 20". The muzzle threads are ½"-28 tpi, and in the back a standard rifle barrel extension is pre-installed. 5.56 NATO chamber (also accepts .223 Rem) Original 1-12" rifling compatible with heavier bullets Chrome-lined bore Requires a rifle-length gas tube (available separately) Available as Stripped or complete Barrel Assembly This Brownells Retro A1 rifle barrel is machined from ultra-strong 4150 chrome-moly steel, and is magnetic particle inspected when finished to ensure there are no hidden flaws that could shorten its service life.

Backorderable

Backorderable, delivery time approx. 4-12 weeks from the USA warehouse.

100-Day Return Policy

No charges until we ship

No charge:
Your credit card will not be charged when you place your order.

No commitments:
You are under no obligation until the goods are shipped. You can cancel your order at any time before shipping - free of charge.

Not until shipping:
Your credit card will only be charged once we ship your order. Not before.

Wish List Ask question

order by phone

279.9 279.9 1 GBP

Description Specification Customers reviews Accessories

BROWNELLS BRN AR-15/A1 5.56MM 20" 1-12 TWIST RIFLE BARREL ASSEMBLY

279.9 GBP £279.90

Prices inclusive of duty & VAT.

Is a 'Call to order' product.

Requires order by phone

Description:

Introducing the ultimate Retro A1 rifle barrel for your AR-15 build!

The Brownells Retro A1 rifle length barrel is designed to replicate the original "skinny" barrel of the M16A1 rifle, making it perfect for constructing your own Retro Rifle™ or any AR-15 where a lightweight barrel is desired.

Key Features:

Caliber: Chambered in 5.56x45 (also accepts .223 Rem)
Twist Rate: 1-12" rifling compatible with heavier bullets
Bore: Chrome-lined for durability
Length: Overall length of 20"
Muzzle Threads: ½"-28 tpi
Gas Tube: Requires a rifle-length gas tube (available separately)
Assembly Options: Available as Stripped or complete Barrel Assembly

This barrel is machined from ultra-strong 4150 chrome-moly steel and undergoes magnetic particle inspection upon finishing to ensure there are no hidden flaws that could compromise its service life. The matte black phosphate finish adds an extra layer of protection and aesthetic appeal.

Upgrade your shooting experience with the Brownells Retro A1 rifle barrel – a perfect blend of classic design and modern performance!

Restrictions

Is a 'Call to order' product.

Top takeaways

The Brownells Retro A1 20" rifle barrel is designed to replicate the original M16A1 "skinny" barrel, ideal for Retro Rifle™ builds or any lightweight AR-15 setup.
Chambered in 5.56x45, it features a 1-12" twist, chrome-lined bore, and matte black phosphate finish, with a ½"-28 tpi muzzle thread and pre-installed standard rifle barrel extension.
Constructed from 4150 chrome-moly steel, the barrel is magnetic particle inspected to ensure quality and durability, and requires a separate rifle-length gas tube.

Attributes

Cartridge:
```
5.56 mm NATO
```
Finish:
```
Black
```
Gas System Length:
```
Rifle
```
Length:
```
20''
```
Muzzle Threads:
```
1/2-28
```
Twist:
```
1-12
```
Weapon type:
```
AR-15
```
Delivery weight: 1.043kg
Shipping height: 25mm
Shipping width: 152mm
Shipping length: 523mm
UPC: 050806029460

Item details

Made in USA
US export classification: 0A501.c

Customers reviews

Customer ratings (4)

4 / 5

Definitely recommended

Excellent 11/10/2018

My experience with this barrel (Brownells No. 100-020-999MB) is excellent. I received mine with an A1 round sight post installed. I paired it with a Colt BCG (No. 160-000-390) with original, surplus handguards, lock washer and 3-prong flash hider. Everything fit well. The barrel nut fits a government wrench and Magpul wrench with no issues. The finish, after 500 rounds, isn't "shiny" anymore - it looks more like a Colt parkerized barrel. My best 100-yard, 5-shot group is 1.56 inches using Hornady Frontier 223 55-grain FMJ. As for the bayonet fit, mine sits 1/16-inch farther back than I think it should but it will work. My M3 bipod fits perfect.

Slightly recommend

After long wait, disappointed. 14/06/2018

Been waiting a year for these to be in stock. It is not true to spec, and required much more fitting than any USGI barrel ever did.

No rollmarks, just the cheesy laser etching UNDER the handguard, where it can not be seen, not even the twist rate or caliber.

Barrel nut was out of spec to the point a barrel nut wrench would not fit. I double checked against several USGI, Colt, Bushmaster, and even PSA. All those were correct, the Brownell's is not.

The spacing from the bayonet mount to the muzzle threading is out of spec, it is about 3/32" too short.

Black shiny, slick finish is not correct. Does not appear to be Manganese phosphate. Machining on the barrel is nothing like the originals when compared side by side.

A2 sight pin? Really?

I am afraid to shoot the thing if this is what they call " an aftermarket barrel made to spec", as it would have failed inspection by gov't purchasing personnel.

Oops! Something went wrong.

We encountered an error while loading this content. Please refresh the page to continue. If the issue persists, contact our customer support.

Site Navigation

Product Categories

Ordering

Customer Service

Connect

Secure payment methods

Trade Associations

Welcome!

to Brownells UK, your destination for anything gun related. With our roots in a genuine passion for firearms, we bring you an unmatched selection of Gun Parts, Firearm Accessories, Gunsmithing Tools, Scopes & Red Dot Sights and Expert Knowledge.

Whether you're looking to maintain, repair, or upgrade, we've got what you need!

For Shooters, By Shooters
We share your enthusiasm and know exactly what you're looking for because we're part of the community.

Massive Selection
From the essentials to the unique, find everything under one roof.

Our blend of tradition and innovation
Shop with the convenience of modern technology, backed by a legacy of experience.

Browse our collection and discover why we're the trusted name in shooting sports & hunting.