BCM® SS410 20" Complete Upper Receiver Group w/ KMR-A15 Handguard (Ionbond BLACK)

MSRP: $1,086.95
Your Price: $918.95
(You save $168.00 )
Maximum Purchase:
10 units
5.56 NATO
Barrel Length:
Barrel Style:
Stock Status:

Out of stock

About the BCM® SS410 20" Complete Upper Receiver w/ KMR-A15 Handguard (Ionbond BLACK)

All BCM® Upper Receiver Groups with a KMR-A Handguard Include:

  • One 3" Picatinny Rail Section
  • One BCM KeyMod Sling Mount

Manufactured by Bravo Company MFG, Inc. (BCM)

These Barreled Upper Receiver Groups are designed for shooting professionals and responsible civilians with the Mil-Spec features for the demands of their duty. They are fully assembled, headspaced, and test fired.
As a note: Prior to shipping, all BCM upper receiver groups are test fired for function, laser bore sighted with a Milspec carry handle for sight alignment within Mil-Specs, and then batch samples are test fired for accuracy. As such, the upper receiver group will show handling marks consistent with these quality control procedures.

SS410 Barrel Steel

This 20" BCM barrel is machined from SS410 stainless steel. Featuring hand lapped 1/8 twist rate button rifling and M4 feed ramps barrel extensions, the 410 stainless barrel gives the shooter the best balance of weight and accuracy. 410 stainless is also harder and more corrosion resistant than conventional 416 stainless found in other commercially available precision barrels.

M4 Feed Ramp Barrel Extension and Upper Receiver

In developing the USGI M4 carbine as one of the primary weapons for today's infantry, some modifications were performed to the original M16 platform to enhance the reliability of the shorter barreled carbines. With the shorter carbine gas system and the increased gas port pressure, the carbine cycled faster, and at times the cycle rate could be faster than the magazine would feed ammunition. One of the modifications done to increase reliable feeding included enhancing the angle and the length of the feed ramps.
This USGI modification was done to both the barrel extension and the upper receiver, creating a longer and steeper feed ramp. These Mil-Spec M4 feed ramps are part of the original CNC manufacturing process. As a result, the factory machined M4 feed ramps on the receiver are hard coat anodized which adds significant strength to the aluminum. This feature is offered on all BCM upper receivers and all BCM barrels.

T-Marked Upper Receiver

The contemporary M16/M4 rifle is built around the concept of modularity. All of the BCM flat top uppers feature a USGI type laser etched T-marks to provide addressing for the remounting of tactical accessories such as optics, laser sights, etc. This enables the weapon platform to be easily configured and then accurately reconfigured for each specific mission.

5.56 NATO Match Chamber (USMC SAM-R Chamber)

The USGI 5.56 NATO chamber is the best choice for effective deployment, reliability, and compatibility, of higher chamber pressures of military or high quality personal defense ammounition.  The SAM-R chamber is the precision version of the 556 NATO chamber.

Shop Related Products:

Want to see more upper receivers? Click the links below to view more BCM® AR complete uppers!


Bravo Company builds: Life Saving Tools™
Copyright 2023 Bravo Company MFG, Inc.
***This product contains chemicals/materials known to the State of California to cause cancer and other reproductive harm. To learn more, visit www.p65warnings.ca.gov.***

14 Reviews

  • 5
    Upper group assembly

    I don't write many reviews, but this upper group and barrel assembly exceeded my expectations. If you want to build an accurate sub MOA rifle this upper rifle group assembly will fit the bill. Once I got it sighted in, I was able to consistently shoot sub MOA groups including some sub 1/2 MOA groups using Federal Premium Gold Metal Sierra Matchking 69 grain cartridges. Bravo Company is known for their quality and now I'm a believer.

  • 5
    Very helpful in picking the right products

    I appreciated the fast and detailed responses I received via email when trying to decide what to purchase. The customer service staff really helped me with making my decision and made the buying process easy. I was also excited to receive the additional swag with my order. The beanie was especially nice to receive. The quality of the product is amazing as well. I have not had any issues and was amazed by the consistency I was getting out of the barrel. BCM has made a customer for life out of me.

  • 5
    I love it...

    Amazing quality in this upper... I expected good accuracy out of this barrel and I was right. With 75gr Match loads I shot a few groups under a half inch at 100yds. Very happy with this rig so far!

  • 5

    Product arrived 3 days after ordering. The first thing I noticed was the quality and attention to detail. I also appreciated all the free swag. love the BCM hat, thanks guys. Fits my Spikes lower perfectly. At first I was discouraged by the accuracy when I was sighting in. I couldn't shoot any better than 3.5" groups using bulk 62gn .223 ammo. With match grade .223 69gr BTHP the gun was EASILY shooting less than 1" groups. Moral of the story, feed this thing good ammo. I'll be using BCM for my next build.

  • 5


  • 5
    Completely satisfied

    Couldn't be more pleased with this incredible product and responsive service through the ordering process. Bravo Company is definitely my first stop. Tremendous product, reputation, and service. Shop with complete confidence.

  • 5

    Great company awesome products! After 5000 rounds down range still holding up and going strong!!

  • 5
    Beautiful upper

    Really pleased with my Upper Receiver Group. I hope to complete my build soon.

  • 5
    Couldn't be happier

    I ordered this upper for my first AR build two months ago. It fit perfectly with my lower build and after 400 rounds of PMC bulk ammo and handholds with Sierra King 69gr bullets, this upper is just amazing. I really wanted the 18" upper with KMR handguard after reading lots of reviews. I'm so glad I went with the 20". I get sub moa groups of .5-.75 inch at 100yds even with PMC 55gr bulk ammo! The rifle length gas system is so easy on the recoil. I ordered the H3 buffer and it's less recoil than my 1873 Winchester shooting .38spc cowboys loads! This thing is a tack driver. Between 50 and 250yds, with iron sights, I can hit anything I want all day long with ease. I can't say enough good things about this upper. I can't wait to buy my 300 blackout from BCM. Delivery, extra stickers, a hat...all timely and perfect. Go BCM!!