Choosing a Platform
Short Story: Choosing a platform is a very personal experience. We have our favorite brand and platforms, and its all we every use anymore.
Assuming that you’ve identified the class of AR that you want, its time to find the best platform for your gun. If you are buying a pre-configured firearm, your options are dictated by the brands that offer complete firearms. If you are building an AR from the ground up, your options are dictated by brands that offer receivers as standalone products. We cannot possibly cover all of the options out there.
We will say that if you want to buy a $300 piece of sh!t off an online gun auction, go for it; but please let us know if you do…we don’t want you covering our asses with a turd of a rifle if we end up in the trenches together. And for your own sake, the difference between BOOM and KABOOM is pretty important.
The Ideal Platform: What to Look For
Your search for an AR platform manufacturer should be focused on the following:
- Compliance with Mil-Spec standards (especially dimensions and tolerances). As described in our What the Spec article, any platform or component must at least meet, if not exceed, the Mil-Spec standard.
- Consistent high quality. You want a manufacturer that makes good stuff. Believe it or not, manufacturers touting Mil-Spec components sometimes churn out absolute garbage that can’t even be assembled properly into a system. Pay attention to reputation and unbiased reviews.
- Enhanced features are a plus. These include features that make it easier to assemble or features that improve the ergonomics or operability of the assembled firearm.
Aero Precision: Our Platform Manufacturer of Choice
We’ve been using Aero Precision for our personal builds for over a decade. Today, we only use Aero Precision platform components in our builds.
Why? That’s easy.
We have tried many brands of receivers and none compare to the combined innovation, buildability, usability, and consistent quality of Aero Precision’s products. Aero Precision products strike the ideal balance between quality and affordability; you can find slightly cheaper products with far inferior quality; you can find much more expensive products with the same (or inferior) quality. Because of this balance, Aero Precision products best support our Mission.
A Legacy of Precision
A Great Track Record
The only issue that we have had with Aero Precision products was a rogue piece of polishing media stuck in the pivot pin spring/detent cavity of one lower receiver, which prevented proper seating of the pivot pin detent spring. Aero Precision quickly authorized the return shipment, investigated the issue, repaired the issue, and returned the receiver at their cost and very quickly. That’s a pretty good track record. Now, that’s not to say that we won’t have any other issues. But, when issues arise, Aero Precision provides exceptional customer support.
In contrast, we have had major issues with other brands. With one brand (which shall go unnamed), the upper receiver takedown pin lug was so far out of spec (it was about 1/4″ too far forward; which is strange for a “Mil-Spec” upper) that it could not be used without substantial modification, which would have compromised its integrity. We don’t ever want our community or customers to have those issues, so we will never use or recommend brands that we have had any substantive issues with.
An Innovative Approach
Our Preferred Platforms
Pistol Caliber (AR-9)
AR-9 Lower Receiver
The Aero Precision EPC lower receiver is purpose-built for pistol caliber carbines, but shares many of the enhanced features of the M4E1 lower receiver. The features are thoughtfully designed and implemented. These features include:
- Threaded Bolt Catch Roll Pin – Allows for simple installation of the bolt catch and virtually eliminates the chance to damage the finish during installation (pin included). 1/16″ Hex Key required for assembly.
- Integrated Trigger Guard – Eliminates the possibility of breaking the trigger guard tabs by integrating the trigger guard into the lower, creating a stronger more rigid platform to build upon.
- Threaded Takedown Pin Detent Recess – Allows user to easily install the takedown pin detent and spring with the use of a 4-40 set screw (no more launching detents across the room or kinking springs).
- Flared Magwell – Increased the flare of the magwell to aid in quick and efficient magazine changes.
- Short Throw Safety Selector Compatible – Marked and milled to accept short-throw safety selectors, but will work with standard selectors as well.
- Pre-Installed Components – Proprietary components pre-installed from the factory.
- Compatible with AR-15 Takedown/Pivot Pins – Standard AR15 takedown/pivot pin lug pattern.
- Glock Mag Compatibility – Compatible with standard frame GLOCK® magazines.
- Multi-Caliber – Can be built as 9mm Luger or 40 S&W.
Most of these enhanced features make assembling, disassembling, and upgrading your lower an absolute pleasure.
The flared magwell and tension screw have an obvious operational value (easy feeding and no “receiver rattle”).
AR-9 Upper Receiver
The Aero Precision enhanced upper receiver comes in two models: the standard EPC receiver with the proprietary handguard mounting lug forged into the upper and the version threaded for a standard barrel nut. After using their proprietary handguard mounting system, we will never use another threaded upper receiver. Below are the highlights of the enhanced upper receivers:
- Last round bolt hold open (LRBHO) mechanism.
- Standard AR15 takedown/pivot pin lug pattern.
- Laser engraved T-marks on the top rail.
- Handguard mounting platform is forged into the receiver. We are absolutely in love with this feature for many reasons (see below).
- Compatible with 9mm Luger and 40 S&W.
AR-9 Handguard
Aero Precision’s enhanced M-Lok handguard is amazing. It feels good, is lightweight, works seamlessly with the enhanced upper, and gives you everything you could possibly want in a handguard. The highlights include:
- Built in anti-rotation tabs, which make alignment and assembly fool-proof.
- Top rail is scalloped to eliminate the sharp edges typically associated with Picatinny rails.
- Continuous picatinny top rail that blends seamlessly with the upper receiver top rail.
- 1.72″ inside diameter (from barrel nut cut to forward end) fits most muzzle devices and 1.5″ suppressors (if the device will be recessed into the handguard at all).
- Compatible with low profile gas blocks.
- Quick disconnect sling socket at the 3, 6 and 9 o’clock positions. Coupled with a buttstock equipped with a QD mount, there is no need for QD attachments, QD end plates, or products (e.g. the Magpul ASAP).
- Additional milling along flats to aid with gripping and add visual appeal.
If you are really stubborn and insist on a threaded upper receiver, you can still use this handguard with the addition of a specific barrel nut interface.
When selecting a handguard length, please refer to our Handguard Length Selection Guide. For AR-9s, we generally recommend 7.3″ for pistols and 12.7″ for carbines, but it depends on the barrel you select and the style you want.
Small Frame (AR-15)
AR-15 Lower Receiver
The Aero Precision M4E1 lower receiver is Mil-spec where it needs to be, and refined everywhere else. The list of enhancements (from Aero Precision) below highlights the improvements over the Mil-spec standard.
- Threaded Bolt Catch Roll Pin – Allows for simple installation of the bolt catch and virtually eliminates the chance to damage the finish during installation (pin included). 1/16″ Hex Key required for assembly.
- Integrated Trigger Guard – Eliminates the possibility of breaking the trigger guard tabs by integrating the trigger guard into the lower, creating a stronger more rigid platform to build upon.
- Upper Tension Screw – Allows users to fine tune the fit of the upper and lower receiver using a nylon tipped tensioning set screw inserted in the grip tang of the lower receiver. This provides a tight fit with any standard AR15 upper receiver.
- Threaded Takedown Pin Detent Recess – Allows user to easily install the takedown pin detent and spring with the use of a 4-40 set screw (no more launching detents across the room or kinking springs).
- Increased Magwell Flare – Increased the flare of the magwell to aid in quick and efficient magazine changes.
- Short Throw Safety Selector Compatible – Marked and milled to accept short-throw safety selectors, but will work with standard selectors as well.
Most of these enhanced features make assembling, disassembling, and upgrading your lower an absolute pleasure.
The flared magwell and tension screw have an obvious operational value (easy feeding and no “receiver rattle”).
AR-15 Upper Receiver
The Aero Precision enhanced upper receiver comes in two models: the standard M4E1 receiver with the proprietary handguard mounting lug forged into the upper and the version threaded for a standard barrel nut. After using their proprietary handguard mounting system, we will never use another threaded upper receiver. Below are the highlights of the enhanced upper receivers:
- M4 feedramps.
- .250 takedown pin holes.
- Laser engraved T-marks on the top rail.
- Handguard mounting platform is forged into the receiver. We are absolutely in love with this feature for many reasons (see below).
- Will support barrels with a diameter up to 1″.
AR-15 Handguard
Aero Precision’s enhanced M-Lok handguard is amazing. It feels good, is lightweight, works seamlessly with the enhanced upper, and gives you everything you could possibly want in a handguard. The highlights include:
- Built in anti-rotation tabs, which make alignment and assembly fool-proof.
- Top rail is scalloped to eliminate the sharp edges typically associated with Picatinny rails.
- Continuous picatinny top rail that blends seamlessly with the upper receiver top rail.
- 1.72″ inside diameter (from barrel nut cut to forward end) fits most muzzle devices and 1.5″ suppressors (if the device will be recessed into the handguard at all).
- Compatible with low profile gas blocks.
- Quick disconnect sling socket at the 3, 6 and 9 o’clock positions. Coupled with a buttstock equipped with a QD mount, there is no need for QD attachments, QD end plates, or products (e.g. the Magpul ASAP).
- Additional milling along flats to aid with gripping and add visual appeal.
If you are really stubborn and insist on a threaded upper receiver, you can still use this handguard with the addition of a specific barrel nut interface.
When selecting a handguard length, please refer to our Handguard Length Selection Guide. For AR-15s, we generally recommend 7.3″ for pistols, 12.7″ for carbines, 15″ for rifles, but it depends on the barrel you select and the style you want.
Large Frame (AR-10)
AR-10 Lower Receiver
The Aero Precision M5 lower receiver is the big brother to the M4E1 platform lower. It shares the same features and enhancements as the M4E1.
- Threaded Bolt Catch Roll Pin – Allows for simple installation of the bolt catch and virtually eliminates the chance to damage the finish during installation (pin included). 1/16″ Hex Key required for assembly.
- Integrated Trigger Guard – Eliminates the possibility of breaking the trigger guard tabs by integrating the trigger guard into the lower, creating a stronger more rigid platform to build upon.
- Upper Tension Screw – Allows users to fine tune the fit of the upper and lower receiver using a nylon tipped tensioning set screw inserted in the grip tang of the lower receiver. This provides a tight fit with any standard AR15 upper receiver.
- Threaded Takedown Pin Detent Recess – Allows user to easily install the takedown pin detent and spring with the use of a 4-40 set screw (no more launching detents across the room or kinking springs).
- Increased Magwell Flare – Increased the flare of the magwell to aid in quick and efficient magazine changes.
- Short Throw Safety Selector Compatible – Marked and milled to accept short-throw safety selectors, but will work with standard selectors as well.
Most of these enhanced features make assembling, disassembling, and upgrading your lower an absolute pleasure.
The flared magwell and tension screw have an obvious operational value (easy feeding and no “receiver rattle”).
AR-10 Upper Receiver
The Aero Precision enhanced upper receiver comes in two models: the standard M5 receiver with the proprietary handguard mounting lug forged into the upper and the version threaded for a standard barrel nut. After using their proprietary handguard mounting system, we will never use another threaded upper receiver. Below are the highlights of the enhanced upper receivers:
- M4 feedramps.
- 0.2795 inch takedown pin holes.
- Laser engraved T-marks on the top rail.
- Handguard mounting platform is forged into the receiver. We are absolutely in love with this feature for many reasons (see below).
AR-10 Handguard
Aero Precision’s enhanced M-Lok handguard is amazing. It feels good, is lightweight, works seamlessly with the enhanced upper, and gives you everything you could possibly want in a handguard. The highlights include:
- Built in anti-rotation tabs, which make alignment and assembly fool-proof.
- Top rail is scalloped to eliminate the sharp edges typically associated with Picatinny rails.
- Continuous picatinny top rail that blends seamlessly with the upper receiver top rail.
- 1.72″ inside diameter (from barrel nut cut to forward end) fits most muzzle devices and 1.5″ suppressors (if the device will be recessed into the handguard at all).
- Compatible with low profile gas blocks.
- DPMS High Profile (.210) Tang
- Quick disconnect sling socket at the 3, 6 and 9 o’clock positions. Coupled with a buttstock equipped with a QD mount, there is no need for QD attachments, QD end plates, or products (e.g. the Magpul ASAP).
- Additional milling along flats to aid with gripping and add visual appeal.
If you are really stubborn and insist on a threaded upper receiver, you can still use this handguard with the addition of a specific barrel nut interface.
When selecting a handguard length, please refer to our Handguard Length Selection Guide. For AR-10 carbines and rifles, we generally recommend a 15″ handguard.
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