Bravo Company Manufacturing M4 AR-15 Upper Receiver Assembly

15 Reviews

In Stock

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The Bravo Company Manufacturing M4 Upper Receiver Assembly is professional grade weaponry. Precision machined to MIL-SPEC from a 7075-T6 aluminum forging provides this upper with exceptional strength. The inside diameter of the receivers threaded bore has been slightly undersized to provide a tighter fit with the barrel extension, resulting in a more accurate rifle.

NOTE: Please use a heat gun or hair dryer to warm up threaded bore of receiver if barrel extension is too tight.

  • Laser engraved T-markings
  • No BCM logo etched on the rear of the rail
  • Marked BCM4 over the gas tube port
  • 7075-T6 aluminum
  • Factory assembled forward assist, and ejection port cover
  • Hardcoat Type III, Class 2 anodized
  • Dry film lube on interior bore per MIL-SPEC
  • Made in the U.S.A.

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BrandBravo Company Manufacturing
Feed RampsM4
FinishHardcoat Anodized
Forward AssistAssembled with Forward Assist
ManufacturerBravo Company Manufacturing
Port DoorAssembled with Port Cover
Receiver Material7075-T6 Aluminum
T MarksT-Marked
California Prop 65 warning

 WARNING: This product can expose you to chemicals, which are known to the State of California to cause Cancer and Reproductive Harm. For more information go to

Ratings & Reviews

15 reviews

  • 3 stars
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  • 1 star
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BCM upper


I used this with two different barres to test and really like it . The fit of the barrel into the receiver was very good and upper worked well with two different lowers.

As stated, a very tight diameter


Fast shipment as always from Primary Arms.I tried to slide in a Spike Tactical 'Optium' barrel into this receiver. Nope, way too tight. I sprayed WD40 on the barrel extension and then convinced it using a rubber mallet with pretty heavy blows. Once it was in, there was no play whatsoever. It felt like the barrel is welded to the receiver. This should really improve accuracy. One star off for the finish. The finish appears botchy and not uneven.

Awesome tight fit. Metal seems a different finish


First off, shipping and customer service is beyond anything I've ever seen. But on to the point of the review.I did give it 5 stars because the product is awesome. As stated it is barely undersized and made for a nice tight grip on the barrel. Used a rubber mallet and block to ease her into place. Definitely only get this receiver if you plan for your barrel to die with this receiver.Fits absolutely perfect with my Colt M4 bottom receiver EXCEPT for the texture of black. Got it together and it nearly matched. Took it for a test run and did my first cleaning and then it stuck out like a soar thumb. I'm hoping it's just new finish and will eventually calm down. But it's merely a personal cosmetic appearance issue so it gets 5 stars and a good review. But definitely be aware it's a different kind of finish black. I'll include picture if I can.



Great price, great product, what more can I say?

Bravo! Bravo!


I just received and assembled my BCM upper, with an 18" SS spiral fluted barrel. The barrel squeezed in, with a little finesse, up to the notch. Once there, I used a rubber mallet to tap it home. All it took was 2-3 light taps, and they seem well mated and supported. I haven't put my hand guard by Diamondhead on yet, but, the barrel is not slipping out. The finish, on the receiver, is a deep charcoal black. Very rich looking, with absolutely no flaws! It was very light, in weight. So much so, that I had to make sure it wasn't polymer. I am very impressed with the build quality, on this unmarked BCM upper. I would rate this higher than the build quality, of either my Stag or Colt. You can feel confident that you are getting the very best your money can buy.

for a "tier 1" build if you believe in that...jv


The bcm upper I received is all that I expected it to be under visual inspection. The t marks are laser etched without depth. I mention this as a colt le6920 user to others of the colts have had t marks etched and cut to depth engraved may be the word..either way just cosmetic..comparable to colt in quality however but many companies stripped receivers are.

Bravo company manufacturing m4 upper receiver asse


Excellent fit & finish and fast shipping


by -

Great fit, but finish leaves some to be desired. Didnt realise it was an unmarked upper so a little disappointed there aswell. Other than those two minor gripes i have it is well worth the money. Finish is like a flat black matte finish almost like charcoal.

Come on guys...


This receiver is undersized on purpose. STOP beating your barrel and or receiver with a mallet. It requires thermal fitting which means you need to heat up the receiver end with a heat gun or hair dryer first to allow the aluminum to expand and then set the barrel in with a little grease on the barrel extension. Then tighten the barrel nut while its still warm. When it cools it will be a nice tight fit.

Excellent quality for a custom fit.


Bought this reciever because it was undersized and BCM quality. Initially my Lothar Walther S/S would not even start to fit. I used a Brownell's lapping bar with valve polishing compound on the receiver face and insde the reciever where the barrel extension mates. Turn the lapping bar by hand go slowly and check the bbl extension fit often . You will get a perfectly square and snug bbl installation without having to use a hammer or excessive force. This product will be my go to reciever for future builds. Tks!