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Table of Contents
- Why do we need a polymer lower?
- Best Pick
- Top 10 Polymer Lower
- #1 JAMES MADISON TACTICAL POLYMER LOWER RECEIVER
- #2 KE ARMS STRIPPED LOWER RECEIVERS POLYMER
- #3 KE ARMS COMPLETE LOWER RECEIVERS AMBIDEXTROUS POLYMER
- #4 KE ARMS COMPLETE LOWER RECEIVERS MIL-SPEC POLYMER
- #5 POLYMER80 LOWER RECEIVER WITH JIG POLYMER
- #6 POLYMER80 POLYMER LOWER RECEIVERS
- #7 POLYMER80 LOWER RECEIVER & JIG KIT
- #8 HYBRID-80 POLYMER REINFORCED LOWER RECEIVER
- #9 BROWNELLS STRIPPED LOWER RECEIVER
- #10 BROWNELLS – BRN-10 LOWER RECEIVER
- Conclusion
The lower receiver is the component that houses the hammer and trigger. The buffer tube assembly should be screwed in and the upper receiver needs to be connected to it at two takedown points. There are three main categories of lower receivers: billet, forged, and polymer.
Why do we need a polymer lower?
Usually, polymer lowers are copies of Mil-Spec forged Aluminum lower receivers. They are constructed from a high-impact composite polymer, which features to save a shape when most lowers bend or break.The typical polymer lower weighs half less than an aluminum billet lower receiver, and significantly less when comparing polymer to a forged lower receiver.
Best Pick
KE ARMS COMPLETE LOWER RECEIVERS AMBIDEXTROUS POLYMER
The Lightweight monolithic polymer AR-15 ambidextrous lower receiver is compatible with all Mil-Spec fire control groups, and cassette-style match triggers.The hammer pin area is wider for long-lasting, but standard AR-15 hammer pins can still be used. The KE Arms mil-spec selector or Ambi selector makes removal easier.There is a great length of pull, and a light, crisp trigger with minimal take-up, clean break, and short reset.
Top 10 Polymer Lower
#1 JAMES MADISON TACTICAL POLYMER LOWER RECEIVER
#2 KE ARMS STRIPPED LOWER RECEIVERS POLYMER
This monolithic polymer AR-15 style lower includes such integral parts as the pistol grip, buffer tube, trigger, and a 13-inch (LOP) buttstock, as well as Pivot and Take Down Pins, KP-15 Selector Detent, Butt plate, and 5/64-in Roll Pin to Retain Buffer Detent. The KP-15 stripped lower receiver is crafted from injection molded, 30% glass-filled nylon, and available in Black or Flat Dark Earth finish. The item can be paired up with 9mm blowback systems with a minimum buffer weight of 5.4 oz (carbine). The lower uses a carbine buffer with spring, a standard bolt catch; it can’t accept the PDQ lever.
#3 KE ARMS COMPLETE LOWER RECEIVERS AMBIDEXTROUS POLYMER
The monolithic polymer AR-15 ambidextrous lower receiver integrates the SLT-1 trigger (4.5-pound pull, sear link technology), Ambi selector, pistol grip, buffer tube, and a 13-inch (LOP) buttstock, flared mag well, and carbine buffer with spring. The SLT-1 will not hit the firing pin with enough force to fire it every time; to solve this issue a weaker spring could be used. The KE Arms KP-15 lowers are constructed from 30% glass-filled nylon (injection molded). The lower receiver can be paired with standard AR-15 uppers in calibers: .300 Blackout, .223/5.56mm NATO, 6.8mm SPC, and 6.5mm Grendel, as well as 9-mm blowback systems with a minimum 5.4 oz buffer weight (carbine). A standard bolt catch should be used, not the PDQ lever.
#4 KE ARMS COMPLETE LOWER RECEIVERS MIL-SPEC POLYMER
The KE Arms KP-15 is compatible with standard AR-15 uppers in calibers including .223/5.56mm NATO, .300 Blackout, 6.5mm Grendel, and 6.8mm SPC, it can be also paired with 9mm blowback systems, when used with a minimum buffer weight of 5.4oz (carbine).
The KP-15 lower receiver isn’t recommended to use for .458 SOCOM, .50 Beowulf, or .50 BMG.
The takedown and pivot pins with built-in detents allow enhancing durability by eliminating the spring and detent holes. The buffer detent is held in place with a 5/64 in roll pin. The KE Arms made the hammer pin area wider to provide longer service life, although standard AR-15 hammer pins can still be used.
The KP-15 lower receiver uses a carbine buffer, spring, and a standard bolt catch (not the PDQ lever). The safety selector spring and detent are loaded from the top, then the selector is slid over them. This Lower is legally classified as a receiver.
#5 POLYMER80 LOWER RECEIVER WITH JIG POLYMER
#6 POLYMER80 POLYMER LOWER RECEIVERS
#7 POLYMER80 LOWER RECEIVER & JIG KIT
#8 HYBRID-80 POLYMER REINFORCED LOWER RECEIVER
#9 BROWNELLS STRIPPED LOWER RECEIVER
The BROWNELLS Lower Receiver is manufactured from original German HK417 forging, and anodized with a matte black, Type III.
#10 BROWNELLS – BRN-10 LOWER RECEIVER
The BRN-10 Lowers are only compatible with the BRN-10 Upper Receivers, not with other 308 pattern receivers. The BRN-10 Aluminum (7075-T6) Lower Receiver allows building out a unique AR-10 clone, including the proprietary components, such as the safety selector, takedown pins, and magazine release. The buffer tube fits any standard AR-15/308 buffer tube and stock.
Conclusion
Customers prefer polymer lowers as they are more affordable than metal lower receivers, despite less toughness. Most polymer lower receivers are largely Mil-Spec compatible. Low-cost and lightweight make the polymer lower receivers more and more popular and commonly used, becoming a workable option for training.
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