BCM® SS410 18" Rifle Complete Upper Receiver Group w/ KMR-A15 Handguard 1/8 Twist

MSRP: $1,042.95
Your Price: $830.95
(You save $212.00 )
Maximum Purchase:
5 units
5.56 NATO
Barrel Length:
Barrel Style:
Stock Status:

About the BCM® SS410 18" Rifle Complete Upper Receiver w/ KMR-A15 Handguard 1/8 Twist

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 18" 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.***

79 Reviews

  • 5
    BCM Uppers.

    I can’t begin to tell you how satisfied I am with my BCM purchase. The process was extremely easy. Plus I received my Uppers in record time with standard shipping. I just want to say Thank you to everyone that works there @ BCM.

  • 5
    Very impressed

    Its very challenging finding quality ar15 rifles so i went on a path to build my own. I got lucky and bought this bcm upper and i found a bcm lower from a gun store in NV.

    I was amazed to see that the lower and upper have a great snug fit. So bcm is building to exact same tolerance that you normally get when you buy a complete rifle.. i also want to comment on the workmanship on the upper its snug fit with bcg and chamber.

    Very pleased with my purchase and glad i was able to find a bcm lower

  • 5
    Excellent every time

    When you buy BCM you know you are getting the best of the best each time. Their quality control is fantastic. Nothing beats BCM

  • 5
    Response to Review Request


    I am happy with the product I received. The build is not yet complete so I cannot yet say everything is perfect.

    I can say I will do business with Bravo Company in the future.

  • 5
    BCM SS410 18” Upper

    The upper shipped to me real quick along with extras that I didn’t know came with it! It came with a BCM magazine/catelog, BCM beanie, stickers, and some lube. The upper actually ran really well and I had no problems with it. This was my first time ordering from them and now I can’t see myself switching to any other company.

  • 5
    Excellent Quality and Lightweight

    Very lightweight for what you’re getting. Put it on my lower and the gun naked weighs 7 pounds. When I added a 1-4 Leupold vx-r, one-piece mount, MBUS, inforce light, the included keymod sling mount and a bcm KAG, the whole package weighed 8.5 pounds. Great for a midrange gun that I can still CQB. Or could push out past 300m with better glass. Love it.

  • 5
    BCM ss41018

    my bushmaster ar15 now shoots that rivals my bolt action 223's .Thankyou for making such a great product !

  • 5
    Upper half

    Zeroed out with a Nikon p223 3x with 62gr 5.56 surplus ammo, 1 MOA all day! My educated guess would be sub MOA with better ammo. I’m hooked on BCM, if I could spare the change I’d pickup their newer ELW complete upper in a 16” middy. Also gotta put a plug in for the KMR alpha rails..... still the best on the market!

  • 5
    Complete upper

    Great. Ordered the upper and it arrived within a week. Excellent fit and finish, fit perfectly with my lower ( which I built). So far about 100 rounds thru it, at 50yrds, five shot groups, all the holes are touching. About 1/4 inch.