Aero Precision M4E1 Upper Receiver and Ambi Lower Pistol Review
It should be no surprise that Aero Precision keeps turning up in my articles. They make some of the highest quality upper and lower receivers in the industry. MajorPandemic.com was actually one of the first editorial sources to feature Aero Precision back when they did not have a website and their primary business was still in aerospace. At that point they were just getting ready to release the COP platform which was licensed by Armalite and now today they make receivers for “many” AR brands you know.Aero Precision has been extremely aggressive with their marketing and has taken full advantage of the surge in sales over the last eight to nine years to become a real powerhouse brand online and offline.
From lower receivers to uppers, to their COP platform to their new design integrated M4 upper and handguard, full based AR rifle builder chassis ready to shoot minus the furniture, fun limited edition lower receivers, a strategic partnership with Ballistic Advantage barrels delivering sublimely made barrels, a couple company acquisitions, and now limited edition builder sets custom cerakoted by Blow Deadline. Aero Precision has been on fire. This AR15 pistol build was to showcase a part of what Aero Precision can deliver to your next build.FIT, FINISH, FEEL, FEATURES, & FUNCTIONS
MajorPandemic.com has reviewed and abused pretty much every one of Aero Precision products in custom builds at one point or another except the M4E1 upper which brings me to this build. Aero Precision M4E1 based uppers are not your typical AR15 upper in that they have a BAR handguard compatible mount forged into the receiver. This one-piece upper combines the handguard mount and upper into a single incredibly strong upper/handguard union. Instead of having a handguard bolted to a collar which is screwed onto the receiver, the handguard is just bolted directed onto the receiver itself and thereby has no contact with any portion of the barrel. 
The system is significantly stronger, overall lighter, and runs cooler than a standard receiver and handguard mount. Another reason for this style of handguard is that it delivers a huge 1.8” internal diameter that will accommodate even largest suppressors and compensators. Although this handguard may seem a bit proprietary, it is actually compatible with other BAR style handguards. For example Seekins Precision and Spikes Tactical BAR handguards are compatible with the Aero Precision M4E1 upper or you could just buy one of Aero’s stunning BAR compatible handguards. Aero Precision M4E1 handguard is a great custom setup which provides monolith level strength with railed, keymod, or MLok rail options. The final large gauge handguard is extremely comfortable to handle, offer improved heat dispersion, and compatibly with any suppressor.
AWESOME BUILDS MADE EASY
Aero Precision now also offers Complete M4E1 Uppers which include a complete factory built upper including barrel and flash hider minus the charging handle and bolt carrier group.
According to Brian Deal with Aero Precision, “Customers often have some particular charging handle and BCG in mind for a build, so we sell the base Uppers without these items, but have them available as add ons.” In this case I slid a Phase 5 Tactical Ambi Charging Handle and Complete BCG into the upper and it was technically ready to fire. I did swap out the A2 birdcage flash hider with a Phase 5 Tactical “FatMan” Compensator which probably the coolest looking comp on the market which also delivers a superb braking effect.
Of course if you have a really cool upper, you need a really cool lower to go with it and I chose the Aero Precision Ambi Lower receiver. If you asked me quietly in off the record, I would tell you that the AP Ambi Lower is the most ergonomic and functionally well thought out ambi AR15 lower on the market. I may even add that it uniquely delivers both bolt release and bolt catch functionality with one lever and is fast and easily masterable with very little practice, but that would be… ya’ know off the record. For this custom AR15 pistol build, the AP Ambi Lower was an easy choice.
CUSTOM TOUCHES
Beyond the Phase 5 Tactical Ambi Charging Handle, Bolt Carrier Group, and FatMan compensator, a super cool Phase 5 Tactical Hex-2C buffer tube assembly was added to the lower. Though the Hex-2C buffer tube features a nice foam cover on half the tube length, I opted to do a midnight blue paracord overwrap. The same paracord was used on my own custom cut down and re-textured A2 pistol grip as well as wrapping the Hi-Lux Micro Max-b-Dot riser.
The featured Hi-Lux Micro Max-b-Dot red dot is an amazing red dot with a 50K+ hour run time, which features a near tint-less tube which in turn provides an extreme amount of clarity and enhanced low light vision. The Micro-Max is extremely compact and comes with flip-up lens covers, kill flash filter, and spare CR2032 battery compartment in the battery cover. For a street price of around $200, the Micro-Max is one of my new favorite red dots.
Other little touches include a KNS JJ Anti-Rotate pin, Seekins Billet Mag Release Button and Trigger Guard, and a HiperFire EDT trigger. The HiperFire EDT are a huge step up from mil-spec with less creep, and a more crisp break all for only around $80 on the street.FINAL THOUGHTS
This build is far from done and destined for a new custom paint job and a few more upgrades so stay tuned. As the build sites, the Aero Precision 1:7 twist barrel (made by Ballistic Advantage) delivered a light and accurate AR15 build that operated flawlessly.
The FatMan comp is loud, however not as loud as expected and not nearly as loud as most other chambered brakes previously tested. My suspicion is that due to the size, the brake is actually partially shielding the shooter from some of the blast which was nice. All around this build was a lot of fun to shoot and turned out to be my lightest AR15 build yet which was an unexpected surprise. The build easily delivered a few 1” 25- yard groups with just the Hi-Lux Micro Max Red Dot with just some PMC Bronze ammo off a sandbag and hammering through the 4”-6” steels at 50-yards was simple. I love this build… now one to the next phase of paint and a few other additional upgrades.SPECS
M4E1 Assembled Upper Receiver
Enhanced Handguard of choice (Keymod, M-Lock, Picatinny)
7.5" 5.56 Pistol Length CMV Barrel, 7.5”, 1 in 7 Twist, 1/2"x28 Threading, Chrome Moly Vanadium, QPQ corrosion resistant finish both inside and out, .750 gas block, Pistol Gas System Length:
Receiver forged from 7075 T6 aluminum
Precision machined to M4E1 specsM4 feedramps
Matte black hard coat anodized Mil 8625 Type 3 Class 2
Laser engraved T-marks
Assembled, with port door and forward assist installed
Accepts standard AR15/M16 components
Handguard mounting platform is forged into the receiver
BAR compatible handguard system
Barrel nut and wrench are included
1pc free float handguard design
Handguard Rail is Machined from 6061-T6 Aluminum
Built in Anti-Rotation tabs on handguard
Scalloped rails
Continuous top rail
1.8" inside diameter fits most muzzle devices and 1.5" suppressors
Chamber: 5.56
MSRP $345 (Includes complete upper excluding BCG and Charging Handle)
Aero Precision Ambi Lower
PDQ Ambi-Bolt Release: Allows user to lock the bolt back as well as send the bolt forward
Material: Military grade steel
Coating: Matte black hard-coat anodized Mil 8625 Type 3 Class 2
Made in the USA
MSRP $165
Other featured Products
Phase 5 Tactical Hex2-C Buffer Tube - $79
Phase 5 Tactical Fat Man Comp - $115
Phase 5 Tactical Bolt Carrier Group - $160
Phase 5 Tactical Charging Handle - $80
Phase 5 Tactical Lower Parts Kit - $65
Paracord.com custom paracord - $10
Hi-Lux Leatherwood Micro Max b-Dot - $249
HiperFire EDT3 Trigger $99
KNS Precision JJ Anti-Rotate Pins - $40
Seekins Precision Billet Mag Release button - $10
Seekins Precision Billet Trigger Guard - $20
SOURCES
Aero Precision - http://aeroprecisionusa.com
Hi-Lux Optics - http://www.hi-luxoptics.com
HiperFire - http://www.hiperfire.com
Phase 5 Tactical - http://phase5wsi.com
Paracord.com - http://paracord.com
Seekins Precision - https://www.seekinsprecision.com