Polymer lower - Opinions?

[Jack Kardic]

A good friend recently picked up a polymer lower from Frontier Armory. He's wanted to make a lightweight, low-cost, KISS rifle as a backup to his pretty heavily accessorized Sabre XR-15. A lightweight, plain except for my beloved EOTech, rifle is just what I happen to be looking for in a new primary. Does anyone have experience with polymer lowers they could throw my way?

[AR-10]

My opinion:

Polymer receivers are fine, if you're putting together a dedicated .22LR

For anything else I want forged aluminum, the difference in weight is negligible when you consider how much strength you lose - if you want a light rifle, pick a lightweight barrel profile and don't go crazy with the handguard or accessories.

[Stickman]

A good friend recently picked up a polymer lower from Frontier Armory. He's wanted to make a lightweight, low-cost, KISS rifle as a backup to his pretty heavily accessorized Sabre XR-15. A lightweight, plain except for my beloved EOTech, rifle is just what I happen to be looking for in a new primary. Does anyone have experience with polymer lowers they could throw my way?


Polymer receivers have not shown themselves to be overly durable.

[markm]

Wouldn't take one for free. I used to ask guys like that if they wanted me to make them a lower out of styrofoam.

[hightowermusic]

Funny, I was there when the same stuff was being said about Glock's. I haven't bought one yet, but first one I find I'll buy.

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[Jack Kardic]

"Polymer receivers have not shown themselves to be overly durable."
-Stickman

Is that in terms of expected round count or standing up to general abuse? I know there's quite a bit of difference in the forces one encounters in rifles vs. pistols, but I've seen Glocks from the 80's with over 100k on the original frame that still chug along fine. And if they are, in fact, crap, who makes some nice light aluminum lowers?

[AR-10]

The Glock was designed as a polymer pistol, and Glocks are not immune from catastrophic failures so that isn't really a good comparison.

Just buy a forged lower from a reputable company (there's really only a handful of companies that forge the receivers for most of the manufacturers out there).

I've been very happy with Mega Machine, their forged lowers are priced right and I've assembled several without issue.

If you want to keep your carbine nice and light, keep it simple but stick with metal receivers.

[tpelle]

Also, the critical parts of a Glock frame are really steel - the slide rails, barrel locking cam, etc. The polymer parts are non-structural, like the grip/mag well, the trigger guard, and dust cover.

On an AR15, the lower receiver has to support the front and rear takedown pins, carry the stress of the receiver extension and recoil buffer, and hold all of the trigger group pins, etc. I wouldn't trust it for long.

Besides, what does it do that a forged aluminum lower doesn't do?

[Hatter]

It seems like the OP was looking to polymer based on weight. Does anyone have some weight values on bare lower receivers; forged vs polymer?

From what I can tell the Plum Crazy composite lower is 1.6 lbs. Does someone have the weight of a stripped T-6 forged lower?

ETA: I don't see a substantial weight savings in the lowers but maybe the data will surprise me. I agree with the comment above. You'll do better setting up the rifle with a light stock, rail and barrel.

[AR-10]

Hatter, msg me your e-mail and I will send you a "weights" spreadsheet that I saved from the Maryland Shooter's group, lots of good info in it.

[OKHammer]

I have a good friend who has a Bushmaster Carbon 15 Type 97S, he loves it and 4000+ rounds later (mostly Wolf) it still functions perfectly.

[Casull]

No one makes a really good poly lower. There's one, but it's so ugly I'm not sure it should exist.

If a company perhaps put more into the lower it might work out. Perhaps metal reinforcement.
There's already really low cost lowers on the market anyhow.

[Stickman]

No one makes a really good poly lower. There's one, but it's so ugly I'm not sure it should exist.

If a company perhaps put more into the lower it might work out. Perhaps metal reinforcement.
There's already really low cost lowers on the market anyhow.


Well stated.

You can't compare Glock receivers with polymer AR receivers, its not even close to the same. Even keeping the idea of one being a pistol and not being subjected to the same abuses as a rifle, it doesn't chance one was purpose built, and the other was not.

[Jack Kardic]

Thanks for all your input. My friend is sticking with polymer, but he's filing SBR and going with a 5.7x28 upper. My hunt continues.

[scottybr]

I have a New Frontier Polymer lower on my AR and it works great. Complete lower with stock, trigger and everything else for $100 shipped (with 5% off coupon).

Pros:


- Obviously the cost. Half the cost of a "low cost" complete aluminum lower.
- Most people don't even notice it's polymer.
- lightweight
- Strong (Which is contrary to what people that have not used them will tell you).
- Scratch resistent.
- Lifetime warranty. This makes purchasing it a no-brainer for me.
- Compatible and upgradable with regular AR parts (triggers, buttstocks, parts kits, etc.)
- About 600 rounds with no problems whatsoever. This lower has not effected accuracy either other than the trigger which is very functional but not a Jewel or a Geissle or anything close.(see below).
- I was able to afford a much higher quality upper. To me having the barrel I wanted was the most important part of my build.

Cons:

- Trigger is too stiff for my liking. If I bear down when I shoot I can still shoot sub MOA groups but it takes skill with this trigger! I would also argue that to get a decent trigger in any AR you need to spend extra anyway.
- All the money I saved just went into a more expensive upper!

All of the guys (that I've seen anyway) that say you need to spend more have not tried these lowers. These are the same guys that will usually tell you "mil spec or nothing" too. There is nothing wrong with that it's good advice if you are somebody that doesn't like to take chances. To each their own I say. To me these are a very good value.

[Jack Kardic]

Never too late. As an update, he ended up getting a 3-pack deal so he built one in 5.7, one in 5.56, and sold the third to me, which became .300BLK. They've variously been dropped on crushed rock, concrete, run over by an F-350, stepped on by a cow, and they all still function fine. I'm amazingly impressed.

[cc99]

Many examples of poly-lowers on ARs can be found with a little digging. The idea of a 5lb AR is a temptation.
Comparing poly-lowers on ARs to Glocks indicates a gap in basic firearm physics... and experience.
Here is one example of a poly lower after 300 rounds of factory ammo:

http://farm9.staticflickr.com/8338/8173334505_fdca1f6027_m.jpg Just isn't worth the hassle &/or hazzard, to me.

[KevinBLC]

From what have read, it seems like the lower is a low stress part. Does anyone have pictures or experience with breaking a polymer lower? Should I just stick with aluminum lowers?

[browcs]

I have a New Frontier lower mated to a Tactical Solutions .22LR upper, making for a very light training rifle.

[UWone77]

I would never use a polymer AR lower based on what's available now. They maybe ok for "plinkers" but I view all of my weapons as fighting guns and would not hesitate to use any of them for HD or duty. Polymer AR lowers just don't cut it for me.

[John Hwang]

The buffer tube housing is where most of the polymer lowers fail. There are some products in design phase we can't talk about but certain key structural areas need to be addressed on current designs IMO.

[Pork Chop]

I think anytime someone "thinks" outside the box, there are going to be those to shoot it down. I see no reason why a polymer lower wont work for anything smaller than 7.62x39. Besides, we don't all have an unlimited budget like some of you, I guess.


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[UWone77]

I think anytime someone "thinks" outside the box, there are going to be those to shoot it down. I see no reason why a polymer lower wont work for anything smaller than 7.62x39. Besides, we don't all have an unlimited budget like some of you, I guess.


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Nothing wrong with thinking outside the box, however, just because you think outside the box doesn't mean it's a great idea. This has nothing to do with "unlimited" budgets, Polymer lowers simply have a lot left to be desired. Once a viable design comes out, I'd be more than happy to entertain it, use it, and buy it. Until then, polymer lowers in my opinion, just don't cut it.

[Pork Chop]

Nothing wrong with thinking outside the box, however, just because you think outside the box doesn't mean it's a great idea. This has nothing to do with "unlimited" budgets, Polymer lowers simply have a lot left to be desired. Once a viable design comes out, I'd be more than happy to entertain it, use it, and buy it. Until then, polymer lowers in my opinion, just don't cut it.

What don't they "cut"? From the torture tests I've seen, they hold up just as well, and better than the equivalent aluminum lowers. However, only time will tell how they actually hold up thru thousands of rounds and what not. I am using one for my AR that I'm currently building. So I have no input to their longevity. I simply bought it because it was cheap and I'm on an extremely tight budget.


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[John Hwang]

Pork Chop, maybe there are some really nice polymer lowers now and we just need to be educated on what's available today. I'm only remembering what I've seen in the past.

http://i690.photobucket.com/albums/vv265/THEPATRIOT-X/PClwr.jpg

http://i690.photobucket.com/albums/vv265/THEPATRIOT-X/cavarmslower4.jpg

http://i690.photobucket.com/albums/vv265/THEPATRIOT-X/DSCN0312.jpg




But doing a little research today, I saw this video of the New Frontier Armory lower that looked promising


http://www.youtube.com/watch?v=CEAYW_2y4VU&feature=channel&list=UL

[Pork Chop]

Yeah, I have the NFA LW-15 polymer lower. I had heard bad things about the Plum Crazy brand so I stayed away. This is mine thus far:http://img.tapatalk.com/d/12/11/15/yzu9eze3.jpg


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[Jack Kardic]

One thing I've noticed is that the polymer buffer tubes seem to have a lot less rattle/pinging. I don't shoot AR's a lot, and I've always been bothered by the feel of the buffer moving nest to my face, but it gets dampened quite a lot and feels smoother overall.

[KevinBLC]

The plastic lowers seem good for the money. What brands should I consider for my first build?