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BRN-4 STRIPPED UPPER RECEIVER BILLET Reviews & Ratings

Assemble your own BRN-4 Upper Receiver Assembly

Machined from billet aluminum the new BRN-4 Stripped Upper Receiver mates perfectly with the Brownells BRN-4 barrels, gas system components and bolt carrier group. Assemble a BRN-4 Upper Receiver Group from all new parts, no more relying on surplus, used components. Precision machining of the billet aluminum gives the appearance of a forged part, with finely mapped contours, leaving no unecessary flat surfaces or sharp edges.

Matte black hardcoat anodizing. Anodizing meets or exceeds mil-spec requirements for thickness. Laser engraved T-Marks and BRN-4 logo.

Fits standard AR-15 & M16 Lower Receivers. Accepts standard AR-15 & M16 ejection port covers and forward assists. Does not include Op Rod / Upper Receiver Bushing (sold seperately).

Requires BRN-4 Upper Receiver Bushing (078000700)

Compatible with early style, HK^®416 (A1-A3) barrels and barrel nuts.

PLEASE NOTE: This is a Billet Receiver, machined from a solid block of aluminum. As a result, it will show machine passes on some of the more complex geometry. These are intended to retain the overall exterior dimensions of a forged part. These surfaces are prepped by bead blasting to reduce the profile of any machining prior to anodizing.

See all of our AR15s and AR15 parts here.

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Reviews Summary

The BRN-4 Stripped Upper Receiver Billet offers good performance and fits a budget, but many users report quality control concerns, primarily with machining and fit issues. Customer service is praised, especially regarding returns and replacements. Overall, while some are satisfied, others caution it may not meet the quality of genuine HK parts.

What Reviewers Are Saying

Product Quality

65%

Many reviewers note quality concerns, particularly regarding machining marks, anodizing thickness, and fit specifications. Some received out-of-spec products that affected compatibility with other parts, while others encountered only minor issues. Despite these concerns, most agree the product functions well within its intended purpose.

Customer Service

70%

The customer service experience has received positive feedback, with users highlighting helpfulness during the returns and exchange processes. Many reported prompt responses and resolutions to issues, which adds to overall customer satisfaction despite initial product problems.

Fitment Issues

55%

Fitment problems, such as loose fitting with parts and alignment issues, are frequently mentioned. Reviewers noted that the upper receiver often does not align properly with lowers or other components, leading to potential operational issues.

Value for Money

50%

Consumers generally feel that the BRN-4 upper receiver offers decent value considering its lower price compared to original HK parts. However, some feel that the discrepancies in quality may warrant buying higher-end products instead.

Aesthetic Concerns

45%

Several reviews mention the upper's aesthetic quality, particularly the visible machining marks and the anodizing finish. While some users accept these imperfections as expected from a budget option, they still dampen the overall perception of quality.

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Quality improved?

While I haven't had the privilege to fire mine yet, the quality of this upper of a better than expected quality given the price and niche. Plus, its got that sexy 416 height, you just can't get that anywhere else

Would you recommend this? Yes, I would recommend to a friend

by Brian on July 30, 2025

Verified Purchase

Was this review helpful? 0

Nice upper!

Great, I missed the sale by two days, but it is still great!

Would you recommend this? Yes, I would recommend to a friend

by DANIEL SUMMERHILL on August 02, 2024

Verified Purchase

Was this review helpful? 0

Not sure what the big deal is

All the low review ratings on here talk about how bad the machine marks are, but in reality, they're barely noticeable, and even if they do look rough, they don't even catch a fingernail. The finish is very nice, and when assembled, the action is very smooth.

by COLIN ZIMMERMAN on November 22, 2023

Verified Purchase

Was this review helpful? 2

Well Built

Impressed with the quality and tolerances with this product. 100% interchangeable with HK 416 or MR556 build projects.

by JOEL BRISKE on October 24, 2023

Verified Purchase

Was this review helpful? 2

Update

Finish and fit this time was great. Received replacement upper receiver, no defects matched up perfectly. I’m happy with the product. Customer service was the best during this process

by Michael S. on May 05, 2023

Verified Purchase

Was this review helpful? 5

Decent Upper Replacement

This upper overall does it’s job. I’m refinishing it so I personally do not mind the machine marks. BROWNELLS PLEASE RELEASE THOSE BRN 4 LOWERS

Buy with confidence

BRN-4 Upper I received was excellent, gone are the old tooling marks and chittering, not 100% smooth but a farcry from what the earlier models were. Only critique is that when I went to install the forward assist, some leftover material came out of the drilled forward assist hole.

Would you recommend this? Yes, I would recommend to a friend

Nice upper but does not come w spacer anymore?

Being a BRN4 billet upper its nice. You barely see machining marks. Comes in a plastic bag in a box but mine did not come with the spacer as shown in the BRN-4/HK-416 Handguard Installation Video on YT. Hopefully the midwest ind rail does not need it but if I do Ill let Brownells know.

Would you recommend this? Yes, I would recommend to a friend

by Mike W on February 22, 2025

Verified Purchase

Was this review helpful? 1

BRN-4 Upper Replacement, (Original out of spec.) - UPDATE

After tightening the HK handguard screw. There is no movement to the handguard at all. Still, the BRN-4 upper handguard locking tab should be a tight fit.

BRN-4 Upper Replacement, (Original out of spec.)

I received my replacement part for the BRN-4 Upper receiver two weeks ago because it was out of spec. (the bolt carrier will not go into battery). The new one did fix the problem, but I notice that the locking tab of my HK 416/MR556 Handguard that I bought from Brownell's has a little play in it. The handguard is able to move slightly left and right (its bugging the heck out of me). I also bought an HK MR556 Upper after I send in my original upper back for replacement (it was on back order until who know when) and have tested on it and it has no movement at all. I think the locking tab on the new BRN-4 Upper is a little wide.