The AR15 rifle was first designed by Armalite in the 1950s to pursue a US Military contract for a new service rifle to replace the M14. Facing bankruptcy, the company sold the design to Colt’s Manufacturing Corporation who went on to provide a select fire version for the US Military designated as the M16.
Later, Colt retrojected the AR15 rifle into their lineup as a semi automatic only version intended for civilians. The design of the bolt carrier was changed and the lower receiver had a few modifications, notably a hinged front pivot pin, the lack of a third hole in the fire control group to accept the automatic sear and a two position selector lever that pivoted between “safe” and “fire” as opposed to the military’s three-position safety.
Manufacturers and Companies that Make Lower Receivers
There are more than 50 companies that manufacture an AR 15 variant. Some of the most common are: Colt’s Manufacturing Company (Colt), Armalite, Bushmaster Firearms International, Bravo Company, CMMG, Olympic Arms, Daniel Defense, DPMS Panther Arms, Les Baer, Elite Arms, Wilson Combat, JP Enterprises, Heckler & Koch, Knight’s Armament, Seekins Precision, La Rue Tactical, LMT, Noveske, Rock River Arms, Remington Arms, Mossberg, Ruger and Spike’s Tactical.
While some companies push out mere clones of their competitors’ product, others strive to bring something different to the table with their offerings.
Federal Firearms License Information
The lower receiver is the serial numbered part which makes the AR-15 a firearm and with very few exceptions is the only part that requires shipping and receiving through a Federal Firearms Licensee (FFL). Most of the lower receivers available look extremely similar to one another, leading to the misconception that all are manufactured by a few entities in the industry.
In addition to the rifle’s serial number, the lower receiver contains the magazine well, fire control group (hammer, trigger, sear and safety), buffer tube, stock and the bolt catch. Lower receivers may be had either stripped or complete. There is even an option for “less complete” versions for the ultimate “do-it-yourself” project.
The Top AR 15 Lower Receivers
Spike’s Tactical produces AR-15 lower receivers for consumers and law enforcement and was one of the first companies to cater to the growing NFA oriented segment of the shooting public.
Spike’s machines their receivers from a mil-spec aluminum forging with an anodized finish to resist wear and tear from the elements. The magazine well is engraved with Spike’s spider logo and the caliber designation: “Multi” to allow shooters to adopt any caliber within reason.
One of the more recent manufacturers specializing in custom AR15 lower receivers is Seekins Precision. This lower receiver features a textured magazine well front to allow the shooter to use it for stability instead of the hand guards. Completely designed with the tactical shooter in mind, this completely mil-spec lower receiver known as the SP223 is worth the extra cost.
The SP223 lower receiver includes an oversized trigger guard for use with gloves and the best part of all is Seekins’ use of screws as opposed to roll pins to complete the build, which results in less potential damage to the receiver during assembly and is a vast improvement over every lower receiver on the market.
CMMG has been manufacturing quality lower receivers and complete rifles for a number of years and specializes in calibers other than 5.56 NATO. Their 9mm lower receiver is machined from a billet of T-6 aluminum and accepts all mil-spec parts, but requires the use of a 9mm buffer spring. The magazine well accepts Colt 9mm magazines but may be modified to use Uzi 9mm magazines as well.
4. DPMS LR-308
Technically this lower receiver may not be for an AR15, but it is worthy of mentioning due to the surging interest in this type of rifle chambered in 308 Winchester. In some circles it is known as the older and bigger brother to the AR15: the AR10, whose name is trademarked by Armalite. As it is intended for a larger caliber than 5.56 NATO with a longer cartridge case, some changes had to be made to the lower receiver, including the provision for a longer magazine well.
Besides that, the receiver accepts all the parts of an AR15 lower receiver parts kit and a few modifications have been made to make the installation easier such as threading the bolt catch instead of using a roll pin and relocating the rear take down detent to beneath the pistol grip as opposed to behind the butt stock in a position that begs for a crushed spring and lost takedown detent, unless you have three hands.
As for upper receivers to fit this model, they must be chambered in 308 Winchester. Larger caliber AR15 upper receivers intended as single shot rifles in 50 BMG or 338 Lapua will not fit on this version, either.
As mentioned previous, most AR15 lower receivers transfer the same as a complete firearm with few exceptions. That exception is the 80% lower receiver. This is an aluminum forging that has 80% of the final work done to it. The buyer must complete the remaining from drilling the hammer and trigger pins to milling or cutting out the section for the fire control group.
When it is complete, the buyer may need to serialize and register it depending upon their city and state of residence. It is the buyer’s responsibility to comply with federal, state and local firearms laws.
There are a number of choices when it comes to a lower receiver depending upon how much work the buyer wishes to put into their build. From complete lower receivers with all parts including the butt stock installed to 80% lowers that require a degree of milling, drilling and final finishing before installing a lower receiver parts kit. There is even a raw forging available which requires an inordinate amount of work for the hobbyist to complete.
It cannot be said that there are little to no options when it comes to choosing a lower receiver for an AR15 project.