The AR-15 lower receiver has remained largely unchanged for decades. The USMGM MG-15E introduces a new approach to AR-15 controls with the Sabre System—an innovative ambidextrous bolt catch and release system integrated directly into the trigger guard, designed around speed, ergonomics, and minimal movement of the firing hand.
The MG-15E is built as a fully ambidextrous AR-15 lower receiver when paired with an ambidextrous magazine release. The centerpiece of the design is the Sabre System, which uses a low-profile finger pad positioned directly behind the magazine well. This unique control placement allows the shooter to lock the bolt to the rear, release the bolt, clear malfunctions, and perform reloads without the excessive hand movement required by more traditional bolt manipulation solutions.
Constructed from 7075-T6 billet aluminum, the MG-15E combines a durable, precision-machined foundation with a refined control layout focused on real-world performance.
In this video, I take an in-depth look at the USMGM MG-15E lower receiver, demonstrate the Sabre System in use, and compare its design against other popular AR-15 control solutions.
I compare the MG-15E against the Aero Precision M4E1 lower receiver and compare the Sabre System finger pad against the Magpul BAD Lever and the SIG MCX-LT ambidextrous bolt catch lever to see how these different approaches to bolt manipulation compare.
In this video, I cover:
• USMGM MG-15E ambidextrous AR-15 lower receiver overview
• 7075-T6 billet aluminum construction
• Sabre System ambidextrous bolt catch and release demonstration
• Trigger guard-integrated finger pad design and ergonomics
• Full ambidextrous capability with an ambidextrous magazine release
• Locking the bolt to the rear and releasing the bolt with minimal firing-hand movement
• Sabre System vs. Magpul BAD Lever
• Sabre System vs. SIG MCX-LT ambidextrous bolt catch lever
• USMGM MG-15E vs. Aero Precision M4E1 lower receiver
• Threaded rear takedown pin spring and detent hole
• Threaded bolt catch pin
• Integrated trigger guard
• Flared magazine well
• M16-cut lower shelf
• Nylon-tipped receiver tensioning screw
• Premium anodized finish designed for hard use
• Low-profile aesthetics
• Ephesians 6:10 engraving beneath the grip
• USMGM’s veteran-owned, faith-first approach to firearm design
The USMGM MG-15E represents a different direction in AR-15 lower receiver design by focusing on control placement, ergonomics, durability, and practical improvements to how the rifle is manipulated.
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What are your thoughts on this lower receivers features and the Sabre system?
Is the primary bolt release proprietary or can you swap it out with a off the shelf bolt release?
Or….you could have just bought an ADM UIC 15 years ago and saved a lot of money (I got my two lowers back then and they weren't even $300 a piece). I've used them heavily (one a pin and weld 13.9 and the other a 18" DMR) and they've performed flawlessly. I now run FRT's in both and didn't have to do ANY tuning. They just do everything perfectly. I'm sure they'll both out live me.
New frontier Armory has one like this
Bad lever works great, ngl
Had me up until the dumb bible verse.
I'm trying to wrap my head around using your trigger finger to drop the bolt release, when the bolt release can be dropped by the thumb of the support hand at the same time you insert a mag, Maybe if you're one of those weird people that society calls "left handed"..but even then, you should be able to tap the bolt release using your index finger when you're shooting left handed. It's even easier to lock the bolt open if you're left handed because you can lock the bolt using your index finger.
this looks nice.
Really cool lower. Unfortunately, I think it's out of my consideration due to the $325 price tag.
$325 ouch that's like ADM prices.
Look like a good use case for 3d printing metal receivers, as in you can do something like this but grant it an orders of magnitude of addition rigidity.
Will the ambi part of the bolt release interfere with a @limasix upper? If not, this seems like a good lower to pull dual use for swapping between Lima 6 and standard AR
Even better if they made the left side bolt release paddle stick out far enough to clear the lima 6 too so I wouldn't have to break it off / replace it
I’m still happy with my Aero lowers. But not everyone had the foresight/stupidity to buy a Bajillion lowers of the M4E1
0:38 the upper receiver tensioning screw has aftermarket products where there is a ball bearing in a spring that presses upwards. To me it’s so cool because it makes it so the upper is firmly secured, but also doesn’t put excess pressure needlessly into the upper and lower. It’s just a spring inside the screw pushing on the bearing inside. “Slotted 440C Stainless Steel Ball-Nose Spring Plunger with Steel Body, 1/4"-28 Size, 4-12 Ib. Nose Force.
want one, too much for a stripped lower though
Have you tried the Phase 5 EBRV3 yet?
I remember seeing a patent about this a few years ago but it was done with the vertical slide in the middle not off to one side
Great coverage on the lower, Tim! Probably the most detailed video I've seen so far, and I appreciate the straight-to-the-point style. Glad you like the lower.
Very cool
I need one
The hk or dark storm amdi catch is better, no additional moving parts but full functionality
Simpler and safer, more reliable
Just another part to break
My Robinson arms Xcr-L has this lol way better. But good upgrade for an AR
Integrated trigger guard sucks. I wanna put my favorite trigger guard, lol …
Yeah it doesn't even come close to as good as a Griffin MK2 or an ADM UIC especially for that price.
I appreciate how to the point this video was.
Similar to the Magpul Masada/Bushmaster ACR ambi lower receiver.
So it’s a normal lower with a proprietary bad lever like device
very nice receiver, just "way" over priced!
Very cool but not $325 for a lower cool. The Magpul Masada had a better design back 2007.
THAT'S THE FUCKING MAGPUL ACR STYLE BOLT RELEASE SOMEONE FINALLY MADE IT
Using an empty mag adds a few pounds to the release of the bolt hold open.
seems a bit odd to retain the original bolt catch. no need for two different controls that do the same thing. reminds me of how the sig xm7 has two charging handles.
AR doesn't stand for Armalite Rifle btw
1:32 FOSSCAD respect gained
That's NICE.
Super safe ready?
Nothing wrong with the bad lever but i definitely like the threaded portions and set screws to keep springs from shooting out. Id definitely be interested in getting one of these lowers.
Good video 👍🏻
Just bought a griffen the other day. It’s cool though I love to see innovation..
Nice review! As a lefty I’m glad we are finally getting some love. Right now I have a bad lever and use it in the reverse if that makes sense. But this is far superior. I have a troy ambi mag release because it’s one of the few ambi mag releases that work with the bad lever and it’s ok. But the forward controls design looks a lot nicer since it sits further back. But it is not compatible with the bad lever.