Bravo Company Manufacturing M4 AR-15 Upper Receiver Assembly

As others have said, good BCM quality without issues. The ID of the bore is definitely tight, and MUST be heated to accept a barrel extension. A hairdryer wasn't enough for me, so I cooked the threads under a MAP torch for a few seconds and it slid right onto my frozen barrel extension. The finish is a slightly blotchy charcoal grey, a little lighter than other black anodized parts that I have used. Not a problem for me as I spray paint my builds.

I've used these upper to yield accurate builds. The trick to fitting the barrel to the receiver is to heat the receiver in the oven at 200 degrees F for 20 minutes and put the barrel in the freezer for 20 minutes. When time is achieved, put on some oven mitts, remove the barrel from the freezer and remove the receiver from the oven an IMMEDIATELY insert the barrel into the receiver WITHOUT APPLYING ANY GREASE OR OIL ! You'll hear a "snap" or "pop" as the receiver cools quickly and hugs the barrel. The result is a tight fit without slop. The resulting accuracy is worth the process.

BCM quality is second to none. This upper receiver shows it, but not their BCM logo- little disappointed about that, but no big deal. Barrel fitment is snug but easily installed if you follow their instructions. I installed an FN barrel with this upper and covered it with their MCMR MLOK handguard. Overall, this a very nice upper receiver that I would highly recommend. Pricing is always good at Primary Arms— thank you-Semperfi

Excellent fit and finish, super snug fit with my SOLGW barrel. It had a instructions sheet saying you might need to heat it but I didn’t think I would need to lol. Sho nuff had to give it some heat.

LET ME TELL YOU... I did not have fun with this upper. Trying to get a 16" FN Barrel in took forever. The information that comes with the upper suggests a heat gun "might" be needed. No, it is. I went the round about way and had my brother help me by blasting the upper with a blow dryer and slowly working the barrel in with a mallet. It got there but it wasn't fun.

The fit of this barrel is maybe too good. It took me a long time to get the barrel in but it was worth it. I could not ask for anything better here.

Receiver is a bit undersized but BCM did that on purpose. I borrowed the wife’s hair dryer to heat up the aluminum a little and my barrel slid right in with no issues.
I will definitely be buying more of these for my future builds.

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!

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.

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.