With demand at an all-time high, SilencerCo chose the perfect moment to launch its new AR-15 stripped lower receiver, the SCO15. Silencer Shop got their hands on a couple of samples (if you’re interested in snagging one once they’re in stock, join the mailing list here) and I was lucky enough to borrow one and build it out for testing.
Machined from billet 7075 aluminum and Type III Hardcoat anodized black, the SCO15 lower receiver has a few unique tricks up its sleeves.
Typically a stripped lower means no parts whatsoever are included, but in the case of the SCO15, it comes with its own completely ambidextrous bolt catch. Passing through the top of the receiver and out the right side, this bolt catch allows the shooter to manually lock the bolt back as well as release the bolt from lock very easily with a single finger.
For a right-handed shooter, the placement and shape of the right-side lever is ideal for operation with the trigger finger. Push up on the bottom of the lever to lock the bolt back, push down on the top to release the bolt.
On the left side of the receiver, the bolt catch design is faithful to mil-spec. It ships uninstalled, so you’ll need a standard lower parts kit spring, detent, and roll pin to hold it in place.
One final note of interest: the bolt catch is “3D-printed” (laser sintered) from 17-4 stainless steel.
Starting with a big block of aluminum rather than a forging that’s nearly in final form allowed SilencerCo to machine some unique features into the SCO15.
One standout is ambidextrous, anti-rotation QD sling cups integrated into the rear of the receiver. Very cool.
Also seen in the photo above, though certainly not limited to billet lowers, is a unique safety selector “Fire” marking that works with both 45-degree and 90-degree throw safety levers (or any in-between).
The SCO15 features a large, integral trigger guard with a comfortable flare at the rear for the shooter’s middle finger support and a flared front that flows nicely into an enlarged magazine well funnel.
Above the trigger guard is a similarly-shaped flare that protects the magazine release from accidental activation. And, sure, it also looks cool as it flows from there up across the top of the magazine well where it houses the spring and detent for the pivot pin.
Up front, the shape of the flared magazine well and deeply chamfered receiver edges feel good in the hand for you weirdos who like to hold the receiver while shooting instead of, you know, the aptly-named handguard.
Of course, the purpose of a stripped lower is to turn it into a complete lower, and then turn that into a functional rifle or pistol. Under the bright lights of Silencer Shop’s studio, filming a video on how to assemble a stripped lower receiver, I built out the SCO15.
Robbing these components from Black Collar Arms, I installed an ERGO Enhanced Lower Parts Kit, an ELF-SE Trigger with straight shoe, and an ERGO Swift Grip. From my personal spare parts department I grabbed the awesome Lancer Systems Carbon Fiber Fixed Stock.
Assembly on the SCO15 was smooth and typical. The only unique aspect of assembling it is the takedown pin detent — it goes up through the bottom and is held in place by the pistol grip instead of inserting through the rear and being held in place by a receiver end plate.
Had I designed the SilencerCO SCO15 stripped lower receiver there’s really just one, minor change I would have made. Instead of a hammered-in, traditional roll pin / split pin for the bolt catch I would have gone with the more modern, easier-to-install shoulder screw system.
Not a huge deal, but I happened to struggle a little with this part of the assembly thanks to either a slightly oversized pin or an undersized pin hole, so between some light swearing and some heavy hammering I pined for that shoulder screw. Additionally, the rear QD cup made it harder to align a punch properly and drive that pin in, which didn’t help.
I’d definitely recommend using masking tape to protect the QD cup and the area around the bolt catch from assembly-induced finish damage.
I slapped on an Adams Arms upper and headed to the range.
No surprise here; everything ran great. The SCO15’s flared magazine well made mag changes easier, and the bolt catch functioned flawlessly from the right side. Easy to lock, easy to drop.
SilencerCo is machining the SCO15 in-house in their Utah facility, and the machining quality is great. I found no tool marks or mistakes anywhere; just smooth, clean aluminum. Likewise the hardcoat anodizing is a flawlessly consistent, deep black.
With an MSRP of $249, SilencerCo is targeting the premium end of the market. Of course, this is unquestionably a premium receiver with unique features like the ambidextrous bolt catch and integral QD cups, plus that SilencerCo logo that we aren’t used to seeing on a receiver. They’ve also launched it at a time when AR-15 parts demand is through the roof and inventory is low, so I’m positive they’ll sell every single one they’re able to make as quickly as they’re able to make them.
If an SCO15 is in your future, I’d recommend signing up on the Silencer Shop SCO15 page for in-stock notifications. My guess is they’ll be relatively hard to come by.
Specifications: SilencerCo SCO15 Billet AR-15 Lower Receiver
Materials: 7075-T6 aluminum receiver, 3D printed 17-4 bolt catch
Finish: Type III Hardcoat Anodized
Ratings (out of five stars):
Overall * * * * 1/2
SilencerCo’s SCO15 is a great lower receiver with fantastic machining and consistent finish, plus some unique, functional feature enhancements. Sure, I’d tweak that bolt catch to use a shoulder screw instead of a roll pin, or possibly just ship the lower with the bolt catch already installed from the factory, but it’s otherwise a very well thought-out, really nice lower.