polymer lower receivers

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What's the general thoughts on building an AR15 around one of the polymer lowers on the market? Do they tend to offer good durability and reliability or are you really trading out in the name of cost and ease of build?
 
They are currently the same price or more than aluminum ones. It will be a long time before they are cheap enough to even be considered.
 
Yep, What Reddy and hatt said. They are an answer to a problem that never existed. I have personally seen more that 1 that was broken into 2 pieces of useless plastic.
 
Plastic is fine in a lower, if the firearm was designed from the start to take advantage of polymer. The Beretta ARX, SCAR, FS2000, and Galil ACE all use plastic lowers, but they were designed that way.

You can't just substitute plastic for aluminum or steel and expect things to work. Both the AR180B and poly AR lowers have had problems with breaking.

BSW
 
Quote:
Plastic is fine in a lower, if the firearm was designed from the start to take advantage of polymer.
Yep. Polymer AR lowers are a solution in search of a problem.
 
Originally Posted By: bsmithwins
Plastic is fine in a lower, if the firearm was designed from the start to take advantage of polymer. The Beretta ARX, SCAR, FS2000, and Galil ACE all use plastic lowers, but they were designed that way.

You can't just substitute plastic for aluminum or steel and expect things to work. Both the AR180B and poly AR lowers have had problems with breaking.

BSW



NODAK SPUD makes an aluminum lower to replace the poly ones on the AR180B that bust. And I have seen more than one poly lower fail. Usually it is around the buffer tube.
 
From a safety standpoint, aluminum is safer in case of a kaboom. In an aluminum lower, it blows the magazine out the bottom and remains intact. In a polymer lower, the lower explodes and sends shrapnel into the shooters face - saw a case of that somewhere on the net.

The only real benefit of polymer is that it is lighter. If you plan on building an ultra light hunting or field AR that you carry a lot, then polymer might be a good choice. For an every day AR or a defensive firearm, I would stick with an aluminum lower.
 
Originally Posted By: bubbatime
From a safety standpoint, aluminum is safer in case of a kaboom. In an aluminum lower, it blows the magazine out the bottom and remains intact. In a polymer lower, the lower explodes and sends shrapnel into the shooters face - saw a case of that somewhere on the net.

The only real benefit of polymer is that it is lighter. If you plan on building an ultra light hunting or field AR that you carry a lot, then polymer might be a good choice. For an every day AR or a defensive firearm, I would stick with an aluminum lower.


I wouldn't want to depend on a polymer AR lower for anything I actually might want to use, like hunting or field use.

BSW
 
I run a polymer lower. Newest gen model from New Frontier Armory. They are good to go. Run em hard with no issues.
 
Originally Posted By: dwcopple
I run a polymer lower. Newest gen model from New Frontier Armory. They are good to go. Run em hard with no issues.
What is your definition of "hard?" We know forged lowers can handle battlefield conditions.
 
Polymer can degrade when exposed to UV light. That right there makes it a problem for me on a rifle I may have to sling over my shoulder. In a pistol that rides in a holster is less exposed.
 
Plastics can degrade with UV light, but the rate is very slow for ordnance plastics and the pigments protect the plastic too.

For example the Steyr AUG that uses plastic for the entire stock. They've been used for decades without problems in much harsher environments than mine will ever see.

BSW
 
Originally Posted By: bsmithwins
Plastics can degrade with UV light, but the rate is very slow for ordnance plastics and the pigments protect the plastic too.

For example the Steyr AUG that uses plastic for the entire stock. They've been used for decades without problems in much harsher environments than mine will ever see.

BSW


Of course the AUG and other various guns were designed to use those polymers from the start(AUG, G36, TAVOR, etc). The design engineers could take into account the materials and their strengths and limitations when crafting the platform. The weight savings in my opinion are not significant enough to go polymer for an AR lower and there is no cost benefit at this time. I think some people just do it for the shear fact they want to be different.
 
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Originally Posted By: hatt
Originally Posted By: dwcopple
I run a polymer lower. Newest gen model from New Frontier Armory. They are good to go. Run em hard with no issues.
What is your definition of "hard?" We know forged lowers can handle battlefield conditions.


I bought a New Frontier Armory LW-15 lower receiver during the big scare when Aluminum ones were impossible to get. I've yet to put it into a complete build, but I like it for what it is and will finish the build sometime soon.

There are a number of the LW-15 lowers on YouTube undergoing torture tests.

Here is one here: http://youtu.be/duHzeCV32bQ?t=1m54s

Another here: http://youtu.be/ncBnGkjMDJ0
 
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Originally Posted By: Robenstein
Originally Posted By: bsmithwins
Plastics can degrade with UV light, but the rate is very slow for ordnance plastics and the pigments protect the plastic too.

For example the Steyr AUG that uses plastic for the entire stock. They've been used for decades without problems in much harsher environments than mine will ever see.

BSW


Of course the AUG and other various guns were designed to use those polymers from the start(AUG, G36, TAVOR, etc). The design engineers could take into account the materials and their strengths and limitations when crafting the platform. The weight savings in my opinion are not significant enough to go polymer for an AR lower and there is no cost benefit at this time. I think some people just do it for the shear fact they want to be different.



I agree completely. Polymers respond to stress differently than metals, fatigue differently, and handle shock differently. Good engineers the those differences into account when doing a design.

BSW
 
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