The venerable AR-15 platform has come a long ways since its inception in the mid-1950’s. While the first few decades worth of growth within the platform were driven by military necessity through the M-16, the massive sales boom following the sunset of the “assault weapons” ban in 2004 saw a huge influx of R&D dollars. While there are innumerable variations of the AR-15 now, I’d argue that only a handful of these iterative advancements have been truly transformative. One such improvement would be ambidextrous controls, as found in the SilencerCo SCO-15 receiver set.

While Magpul’s BAD lever aimed to bring about the Ambidextrous Revolution in 2012 (despite being beat to market by a knock-off company), it wasn’t until 2014 that San Tan Tactical released the first ambi lower receiver. In the decade that followed, a number of companies have thrown their hats into the ring, including today’s specimen. The SilencerCo SCO-15 ambi lower receiver and matching upper receiver.

Tech Specs, SilencerCo SCO-15 Lower

• Integral Ambidextrous Anti-Rotation QD Sling Cops at Rear of Receiver
• Proprietary Ambidextrous Bolt Catch / Release (Included)
• Enlarged Integral Trigger Guard
• Flared Magazine Well
• Designed for use with standard mil-spec lower parts kit and buffer assembly
• 45- to 90-degree fire selector window for short-throw fire selectors
• Rear tensioner bolt hole (bolt not included)
• Machined in-house by SilencerCo out of 7075 Billet Aluminum

Where To Buy

Tech Specs, SilencerCo SCO-15 Upper

• Precision machined from billet 7075 aluminum and finished in type III hardcoat anodize.
• Features a mil-spec 1913 picatinny rail and M4 feed ramps.
• Compatible with mil-spec forward assists and dust covers (not included in purchase).

Where To Buy

So, the SilencerCo SCO-15 lower is clearly more of a feature-heavy item than the upper. There’s really very little to say about the upper, other than it’s in spec and has functioned just fine. Oh also, there’s some color variation between the upper and lower. Really, it’s more of a light gloss than color. It’s noticeable during unboxing and when the items are brand new, much less so once they’ve been outside. I’ve heard this about type III anodizing before, but here’s the official statement.

“SilencerCo uppers are finished with Type 3 hardcoat anodize, this process forms an extremely hard, abrasion resistant finish. While this finish provides superior results, it can cause some variance in the finish color. SilencerCo can’t guarantee that a SCO-15 Lower will be an exact match with a SilencerCo upper.“

So lets take a look at the lower, the beating heart of this operation.

The trigger guard is enlarged, a given considering how often the Utah-based SilencerCo’s customers (and employees) take these guns into high altitude (and high latitude). Plenty of room for gloved trigger fingers.

The magazine well of the SilencerCo SCO-15 is flared, a near-standard among billet receivers.

QD sling attachment points (cup style) are found on both sides of the lower, toward the rear of the receiver (naturally).

The safety markings are set up for you to be able to use either a 45-degree short throw safety lever or a standard mil-spec 90 degree throw lever. A nice little engraved “window” spans the gap between 46 degrees and 89 degrees of throw. While the lower can accept an ambi safety lever just fine, I didn’t have one to add.

The mag release button is the one item that can be ambidextrous, but isn’t. Standard mil-spec button and location, works as well as it ever has.

The bolt stop/release lever, however, is ambidextrous. Near the magazine release button on the right hand side of the receiver is a small lever that when raised engages the bolt stop. When you hit the lever downward, the bolt drops. This performs the same function as Magpul’s BAD lever, but gets your trigger finger a little further away from the magazine well.

It’s worth taking just a moment longer on the ambi bolt stop/release. This is really the key feature people are going to buy (or not) the SilencerCo SCO-15.

First, let’s cover why there’s a perceived need for a right side bolt stop/release. First, for the true ambidextrous (or simply left handed) shooter, this isn’t really the solution. The way the SCO-15 is designed does provide a big benefit to right-handed shooters over the mil-spec design. Keeping your firing hand on the grip and allowing you to lock and release the bolt with your index finger (while racking the bolt with your left hand) is far faster than taking your right hand off the pistol grip and racking the bolt with it while locking the bolt back with your left hand.

For comparison’s sake, I vastly prefer the SCO-15 to the San Tan Tactical’s design, with STT opting for a button instead of an up/down lever. My experience is that when you’re shooting under stress (and/or wearing gloves), putting two similar sized buttons next to each other with vastly different purposes is a mistake.

Hands On

After assembling the SilencerCo SCO-15 receivers with a lower build kit, a V Seven Weapon Systems Enlightened handguard, the amazing Trident barrel from X2 Dev Group and an AAC 762SDN-6 suppressor mount, I lived at the range for a few days. Barrel testing, optics testing and some fun CQB drills meant I had opportunity to test out every aspect of the SilencerCo SCO-15.

It took me a little bit to get used to the exact location of the SCO-15’s release lever, mostly due to my primary rifle having a Magpul BAD lever for the past eight years. A couple dry fire/malfunctions drill sessions cleared that up easily. The SilcencerCo SCO-15 is a vast improvement in functional speed over the mil-spec design and a more reliable version than the various push-button ambi bolt releases on the market.

The SCO-15 lower receiver did absolutely everything you would expect it to. Flared magwell? Easy reloads. Ambi bolt stop/release? Faster manipulation of controls, hands down. Receivers are not complex parts, and neither is this improved design.

Bottom Line

The SilencerCo SCO-15 is definitely an upgrade over the stock mil-spec AR-15 lower receiver, and I’d argue it’s an improvement over push button style ambi lowers as well. Is it worth the price? That’s for you to decide. The SilencerCo SCO-15 ambi lower receiver runs $269, while the upper runs $219. Both go on sale pretty often. Check em out!

–Check out more articles from Jens “Rex Nanorum” Hammer or visit him on Instagram @Rexnanorum.

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