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Posted: 3/17/2014 7:18:21 PM EDT
I am about to start my 3rd build, and was thinking about going the polymer 80% route. Are there brands to steer clear of? I was planning on going with the polymer 80 brand.
Link Posted: 3/17/2014 7:25:05 PM EDT
[Last Edit: 3/17/2014 7:28:21 PM EDT by 22caliberKIDD]
I personally would never buy a poly lower...ok, maybe for a .22lr build but even that's a big maybe. There are SO many good strong aluminum lowers out there for pretty much any budget so I don't see any upside to getting a poly lower. It's just not my thing I guess.

EDIT- Somehow I skipped over the 80% part when I first read your post. I don't know much at all about 80% lowers so maybe there is some reason to go poly with one of those. Still at the end of the day once you finish up that 80% receiver project you will have a poly lower which is not something I'd personally want.
Link Posted: 3/17/2014 7:27:22 PM EDT
I would never even give one a second look.
Link Posted: 3/17/2014 7:27:37 PM EDT
I see no advantage, therefore no reason to change.
Link Posted: 3/17/2014 7:29:38 PM EDT
[Last Edit: 3/18/2014 4:01:51 AM EDT by Aimless]
I've seen too much of this to wanna mess with one.









Link Posted: 3/17/2014 7:30:28 PM EDT
I know that some feel that aluminum is better, and I used to believe that also. But if the right polymer is used, it would be much stronger, and lighter then forged aluminum. I know first hand, that it isn't really as hard to break a forged lower then you think. And after owning a glock for years, I can tell you first hand that certain polymers are much stronger then you may think.
Link Posted: 3/17/2014 7:32:00 PM EDT
[Last Edit: 3/17/2014 7:34:12 PM EDT by shootertim]
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WOW....Thats gotta suck. Well, Thats what cheap looks like, I guess. I wonder if there are any that are superior to the cheap ones.
Link Posted: 3/17/2014 7:43:42 PM EDT
[Last Edit: 3/17/2014 7:45:43 PM EDT by spyk3]
Hand guns and rifle are two different weapons.

Every brand known to man that has made polymer receivers for ar15 are junk. They usually break at the take down pins.

Your first hand experience on polymer because you've used glocks is useless when it comes to ar receivers.

I've owned a Bush master before and broke after 500 rounds. There was a thread about a guys polymer breaking after 2 rounds.

You asked for a consensus and 90% of people will tell you the same thing...There worthless.

But if you want to question the answer people give you go for it...maybe yours won't break under the 1k count like countless others have
Link Posted: 3/17/2014 7:45:24 PM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By 22caliberKIDD:
I personally would never buy a poly lower...ok, maybe for a .22lr build but even that's a big maybe. There are SO many good strong aluminum lowers out there for pretty much any budget so I don't see any upside to getting a poly lower. It's just not my thing I guess.

EDIT- Somehow I skipped over the 80% part when I first read your post. I don't know much at all about 80% lowers so maybe there is some reason to go poly with one of those. Still at the end of the day once you finish up that 80% receiver project you will have a poly lower which is not something I'd personally want.
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The only real reason I was thinking polymer, is because polymer would be easier to machine on my drill press, but I needed some real input from people experienced. I am seriously re considering, trying aluminum 80% instead. I just figured there was a quality product, and maybe there is, but I really don't want to take the chance.
Link Posted: 3/17/2014 7:58:31 PM EDT
IMHO I would stick to aluminum. Sure you can use polymer or you can print one with a 3d printer, but I don't think the few oz you save is worth the loss of quality in your build. If the poly 80% lowers are cheaper it might be worth practicing on them. You can always throw your failures in the fire and never speak of them again.
Link Posted: 3/17/2014 8:08:10 PM EDT
Maybe one day but not today.........
Link Posted: 3/17/2014 8:11:12 PM EDT
80% Lower build = headache

1. you have to machine it and try not to mess it up (right tools needed with moderate skill)

2. you have to anodize or cerakote or paint it, or find a place to do it for you (If the place is not local = much more hassle to ship it and back)

3. it will cost more and take more time and effort than just buying a decent lower, such as Aero Precision, Spike's Tactical, MEGA, PSA, and so on.
Link Posted: 3/17/2014 8:16:13 PM EDT
Before you buy a 80% polymer lower, make sure that the brand that you buy has a letter of approval by the ATF. EP lowers 80% and Ares Armor was raided last week when the ATF determined that they considered them to be firearms. Customer lists and the polymer lowers were confiscated. That is probably also why Polymer80 is not currently taking orders for thier 80% lowers. If you do not want the ATF to knock down your door, tear up your house, and shoot your dog, or just the legal hassle, be informed about what you buy.
Link Posted: 3/17/2014 8:34:58 PM EDT
Crap. At least until Daniel Defense makes them..
Link Posted: 3/17/2014 9:08:07 PM EDT
[Last Edit: 3/17/2014 9:21:11 PM EDT by Mad_Dragon]
http://www.youtube.com/watch?v=xjhvi8c0MF4

eta: While the CAV15 isn't an 80% lower, it's the only poly lower I'd recommend.
Link Posted: 3/17/2014 9:12:17 PM EDT
I recently completed a poly 80%, only have a couple hundred rounds on it, but so far it's good.

The EP vs ATF issues are covered in the general section and worth reading; I think their tussle with the ATF is due to their MFG method and unique to that method; I ruled them out as crap early on thanks to these forums anyway.

What I chose was the JMT lower from Rainier Arms (link above). I felt that they put a bit more research into strength issues and cast reinforcements in critical areas rather than just copying a metal receiver. There were some issues with the early jigs, but these have been fixed now by 3rd gen jig (see thread in new AR-15 products); the guys at JMT were right on this and even called me direct about how to drill with the older jig that I had. Never a question about the lower, only the jig.

While researching poly lowers, I came to the determination that failures seem to be related to pre-stressing ill-fitting parts then putting into service, and even though mine fit great, I still found a couple areas to finesse the part. I personally saw no reports or threads where the user test-fitted anywhere near as much as I did.

I did not follow exactly the milling instructions, instead I milled the hole(s) to match the rifle which left me with a wall between the rear take-down slot and the FCG pocket and some extra material in the floor and front of the FCG pocket. I figured any extra material can only help strength and durability. If you use a drill press, it is most important that the work be squared to the bit and not just level, can't stress this enough.

The only real concern I have with the poly is the holes for the trigger and hammer pins; this seems like not a lot of bearing surface for a metal to plastic interface if the pins rotate, but then some plastics hold up better than metal in such areas. If I should see wear here, I'll either look into those anti-rotation pins, or I've already located bronze bushings and micro ball bearing to cure wear problems, should they arise.

Link Posted: 3/17/2014 9:29:15 PM EDT
General consensus: Absolute crap.

Personal consensus: Crap and forged/billet is way better, but if one could be had for say $20 then it would work in a pinch. My NFA poly lower was just past the 1K mark before it got replaced with a YHM lower. Going to turn it into a dedicated .22lr, put girly colored furniture on it, and give it to my daughter when she is older

of course by the time she gets it who knows what she will want it to look like...
Link Posted: 3/17/2014 9:35:17 PM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By wine4life:
80% Lower build = headache

1. you have to machine it and try not to mess it up (right tools needed with moderate skill)

2. you have to anodize or cerakote or paint it, or find a place to do it for you (If the place is not local = much more hassle to ship it and back)

3. it will cost more and take more time and effort than just buying a decent lower, such as Aero Precision, Spike's Tactical, MEGA, PSA, and so on.
View Quote


I am one of those people that enjoy building things, I always have. The headache you speak of, sounds like a challenge to me. You are right, it will cost me more effort $$ etc. then just buying an already completed lower. I think the experience to me will make the extra effort worth it....unless I screw up that is.
Link Posted: 3/17/2014 9:41:49 PM EDT
Originally Posted By shootertim:
I am about to start my 3rd build, and was thinking about going the polymer 80% route. Are there brands to steer clear of? I was planning on going with the polymer 80 brand.
View Quote


EP Armory. The general consensus is that polymer lowers are crap. My thought is that they should be used w/ a thumbhole stock, to reinforce the weak spot of the lower.
Link Posted: 3/17/2014 11:49:53 PM EDT
80% are kind of a pain but are a challenge as well. I did one my first build. I'm a 13 year machinist but couldn't use a machine as i don't have one at home, and the company i work for doesn't allow g jobs. I used a drill press to hog out as much material as possible, then used a 1/4" endmill in a trim router. The reason i didn't use my drill press with say a 2 axis vise, is because of the problems a drill chuck presents in holding an endmill. They are not designed for side loads so it's not wise to use an endmill in one. If you can get a drill press or better yet a small mill that can swap a rigid collet in place of the drill chuck, then i would recommend that, but you're likely to get hurt if you try with just a drill chuck.

Trim routers are about $100 though. If you decide to go this route, get a 2 or 3 flute endmill long enough to reach through the jig. Step it down .05 to .1 at a time on depth cuts. Measure your depth frequently. Get a roughing specific endmill for hogging it out, then get a longer flute endmill for a pretty finishing pass. I would get a steel jig as well, instead of aluminum. Far better wear when the shank of the endmill is rubbing up against steel than on aluminum. Get a good cutting oil as well.

I've actually thought that for next time, i will definitely either have a mill, or i will rig up an arm with a z adjustment for the router, plus the router's adjustment, and then mount it on a 2 axis vise. To most that sounds like a lot of work, and a lot of trouble just for an 80% lower, but there's a lot of other things you can do with it also.

Have fun and feel free to pm me if you have other questions. I would do quite a few things differently next time.
Link Posted: 3/18/2014 2:10:32 AM EDT
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Originally Posted By Soulscour:
Before you buy a 80% polymer lower, make sure that the brand that you buy has a letter of approval by the ATF. EP lowers 80% and Ares Armor was raided last week when the ATF determined that they considered them to be firearms. Customer lists and the polymer lowers were confiscated. That is probably also why Polymer80 is not currently taking orders for thier 80% lowers. If you do not want the ATF to knock down your door, tear up your house, and shoot your dog, or just the legal hassle, be informed about what you buy.
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I believe you're missing a huge chunk of that story.
Link Posted: 3/18/2014 2:39:12 AM EDT
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Originally Posted By LunchPail_McSnack:


I believe you're missing a huge chunk of that story.
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Originally Posted By LunchPail_McSnack:
Originally Posted By Soulscour:
Before you buy a 80% polymer lower, make sure that the brand that you buy has a letter of approval by the ATF. EP lowers 80% and Ares Armor was raided last week when the ATF determined that they considered them to be firearms. Customer lists and the polymer lowers were confiscated. That is probably also why Polymer80 is not currently taking orders for thier 80% lowers. If you do not want the ATF to knock down your door, tear up your house, and shoot your dog, or just the legal hassle, be informed about what you buy.


I believe you're missing a huge chunk of that story.


I read the whole story and came to the correct conclusion.
Link Posted: 3/18/2014 2:45:05 AM EDT
For the garabage cans
Link Posted: 3/18/2014 3:17:03 AM EDT
[Last Edit: 3/18/2014 3:17:40 AM EDT by powder007]
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Originally Posted By Soulscour:


I read the whole story and came to the correct conclusion.
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Originally Posted By Soulscour:
Originally Posted By LunchPail_McSnack:
Originally Posted By Soulscour:
Before you buy a 80% polymer lower, make sure that the brand that you buy has a letter of approval by the ATF. EP lowers 80% and Ares Armor was raided last week when the ATF determined that they considered them to be firearms. Customer lists and the polymer lowers were confiscated. That is probably also why Polymer80 is not currently taking orders for thier 80% lowers. If you do not want the ATF to knock down your door, tear up your house, and shoot your dog, or just the legal hassle, be informed about what you buy.


I believe you're missing a huge chunk of that story.


I read the whole story and came to the correct conclusion.


No offense, but i really doubt you come to that conclusion if you have all the facts. At no point in EP's manufacturing process can the lower be considered a firearm by any stretch of the imagination. Since 2012, the ATF has been trying to gain access to Ares Armor's customer lists and have threatened him with jail time and a lot of other stuff, and they are just now raiding his shop to get that list. There is something else going on, another overstep of their bounds. They have too much power and they exercise it frequently.
Link Posted: 3/18/2014 3:40:21 AM EDT
i was thinking about trying one, but i just dont think there are enough pros to justify it. really, there's just one pro, it's lighter. well i'm 30, cutting 5 ounces off the weight of a lower isnt going to be a big deal right now. i'm sure by the time i'm older, there will be all sorts of new tech out there that make them stronger.
Link Posted: 3/18/2014 4:08:53 AM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By powder007:


No offense, but i really doubt you come to that conclusion if you have all the facts. At no point in EP's manufacturing process can the lower be considered a firearm by any stretch of the imagination. Since 2012, the ATF has been trying to gain access to Ares Armor's customer lists and have threatened him with jail time and a lot of other stuff, and they are just now raiding his shop to get that list. There is something else going on, another overstep of their bounds. They have too much power and they exercise it frequently.
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Originally Posted By powder007:
Originally Posted By Soulscour:
Originally Posted By LunchPail_McSnack:
Originally Posted By Soulscour:
Before you buy a 80% polymer lower, make sure that the brand that you buy has a letter of approval by the ATF. EP lowers 80% and Ares Armor was raided last week when the ATF determined that they considered them to be firearms. Customer lists and the polymer lowers were confiscated. That is probably also why Polymer80 is not currently taking orders for thier 80% lowers. If you do not want the ATF to knock down your door, tear up your house, and shoot your dog, or just the legal hassle, be informed about what you buy.


I believe you're missing a huge chunk of that story.


I read the whole story and came to the correct conclusion.


No offense, but i really doubt you come to that conclusion if you have all the facts. At no point in EP's manufacturing process can the lower be considered a firearm by any stretch of the imagination. Since 2012, the ATF has been trying to gain access to Ares Armor's customer lists and have threatened him with jail time and a lot of other stuff, and they are just now raiding his shop to get that list. There is something else going on, another overstep of their bounds. They have too much power and they exercise it frequently.


I already know this. EP does not determine what is considered a firearm. You do not determine what a firearm is. The ATF does. At no point in time did they approve of the EP's polymer lower. To argue in court that their information that they use to make their determination invalidated their determination is a legal battle. This post was about what 80% polymer lower to get. As stated before I recommend the one that doesn't conclude in the last sentence of my original post.
Link Posted: 3/18/2014 4:32:43 AM EDT
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Originally Posted By Soulscour:


I read the whole story and came to the correct conclusion.
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Originally Posted By Soulscour:
Originally Posted By LunchPail_McSnack:
Originally Posted By Soulscour:
Before you buy a 80% polymer lower, make sure that the brand that you buy has a letter of approval by the ATF. EP lowers 80% and Ares Armor was raided last week when the ATF determined that they considered them to be firearms. Customer lists and the polymer lowers were confiscated. That is probably also why Polymer80 is not currently taking orders for thier 80% lowers. If you do not want the ATF to knock down your door, tear up your house, and shoot your dog, or just the legal hassle, be informed about what you buy.


I believe you're missing a huge chunk of that story.


I read the whole story and came to the correct conclusion.


A conclusion, yes. The correct one, no. If you followed the entire story with Ares, and possessed a basic level of reading comprehension, you'd see you were wrong. Go read it again. This time, take your time.
Link Posted: 3/18/2014 4:55:32 AM EDT
This is not GD.

OP try whichever poly lower you want, if it breaks, your not out that much.

I would also get a stripped aluminium lower too for backup.
Link Posted: 3/18/2014 5:14:37 AM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By LunchPail_McSnack:


A conclusion, yes. The correct one, no. If you followed the entire story with Ares, and possessed a basic level of reading comprehension, you'd see you were wrong. Go read it again. This time, take your time.
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Originally Posted By LunchPail_McSnack:
Originally Posted By Soulscour:
Originally Posted By LunchPail_McSnack:
Originally Posted By Soulscour:
Before you buy a 80% polymer lower, make sure that the brand that you buy has a letter of approval by the ATF. EP lowers 80% and Ares Armor was raided last week when the ATF determined that they considered them to be firearms. Customer lists and the polymer lowers were confiscated. That is probably also why Polymer80 is not currently taking orders for thier 80% lowers. If you do not want the ATF to knock down your door, tear up your house, and shoot your dog, or just the legal hassle, be informed about what you buy.


I believe you're missing a huge chunk of that story.


I read the whole story and came to the correct conclusion.


A conclusion, yes. The correct one, no. If you followed the entire story with Ares, and possessed a basic level of reading comprehension, you'd see you were wrong. Go read it again. This time, take your time.


So what do you think is going to happen to the people who purchased the EP 80% lowers? I already said I think they are going to be harassed by the ATF. That is why they confiscated the customer lists. How do you think this is going to end differently?
Link Posted: 3/18/2014 6:23:30 AM EDT
This is going to end w/ the OP's thread locked if you keep arguing about BATFE raids in a tech forum. OP, moral of the story, don't buy an EP lower, and whomever you buy an 80% lower from, ask to see their BATFE Tech Branch determination letter.
Link Posted: 3/18/2014 7:21:10 AM EDT
I built a JMT Polymer lower.

I have several hundred rounds through it and it functions flawlessly,

It was easy to mill on a drill press with a cross slide vise.

There are also some states where milling a metal lower legally requires a manufacturers license... Polymer is legal for anyone though.

Link Posted: 3/18/2014 7:55:13 AM EDT
Link Posted: 3/18/2014 8:27:59 AM EDT
[Last Edit: 3/18/2014 8:32:17 AM EDT by georgio421]
I picked up a Sabre SR-15 polymer rifle lower to go with my Sabre upper just to complete the gun, looks nice works long term?
My real guns have forged or billet aluminum lowers.
If your doing it for something to screw around with thats fine, shtf weapon =no
Link Posted: 3/18/2014 8:29:48 AM EDT
I think the general consensus is that they work fine most of the time,
BUT given the price of forged lowers right now, that are proven, there isn't a decent reason to go with a polymer lower.
Link Posted: 3/18/2014 8:36:54 AM EDT
I bought a finished (stripped) Plumcrazy polymer lower. Some of the lower parts did not fit, some fitting was required. The FCG did not operate correctly it went in the trash. I'm not impressed with them. I will say I remember some of these same problems with early aluminum receivers ie breaking at the pins and at the receiver extension. With todays prices of 49.00 or less for an aluminum receiver I really don't see the benefit of polymer. I believe it will be a few years yet until the bugs are worked out of them. -W
Link Posted: 3/18/2014 8:44:27 AM EDT
I think I have made a decision, I'm gonna go with this http://www.80percentarms.com/products/80-lower-receiver-type-iii-hard-anodized-billet-ar-15

I already have the drill press, and a cross slide vise, the only problem I foresee is my drill press lowest rpm is 530...that may be to fast for some of the steps with bigger bits.
Link Posted: 3/18/2014 8:47:07 AM EDT
JMT has added FDE and OD to their lineup. I was planning on doing my next build with Magpul MOE FDE furniture.....might have to go JMT again (though they aren't in stock at Rainier yet).
Link Posted: 3/18/2014 9:05:26 AM EDT
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Originally Posted By shootertim:
I think I have made a decision, I'm gonna go with this http://www.80percentarms.com/products/80-lower-receiver-type-iii-hard-anodized-billet-ar-15

I already have the drill press, and a cross slide vise, the only problem I foresee is my drill press lowest rpm is 530...that may be to fast for some of the steps with bigger bits.
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Interesting, I do love a DIY project! The guy in the video says 2500 rpm for drill press use, this does seem a bit high to me.
Link Posted: 3/18/2014 9:35:04 AM EDT
I see that OP has been talked into an aluminum lower.

Getting back to his original question about polymer lowers, I've seen recommendations for the JMT and Sabre SR-15.

Regardless of it being 80% or a finished lower, anyone else make a good polymer lower?

Note: I agree that aluminum is both proven and cheaper. I'm only considering the polymer for a .22 and I don't have a polymer lower yet.
Link Posted: 3/18/2014 10:26:35 AM EDT
[Last Edit: 3/18/2014 10:32:15 AM EDT by SinistralRifleman]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By georgio421:
I picked up a Sabre SR-15 polymer rifle lower to go with my Sabre upper just to complete the gun, looks nice works long term?
My real guns have forged or billet aluminum lowers.
If your doing it for something to screw around with thats fine, shtf weapon =no
View Quote


Your Saber Defence SR15 is the same as the GWACS Armory CAV-15 MKII shown in the video below.

Other polymer receivers on the market have done considerable damage to the concept of a polymer receiver in general. That's why I made that video this weekend. The other polymer receivers on the market are not in the same league as the CAV-15 MKII. The CAV-15 MKII can sustain abuse/damage that would put an aluminum receiver out of action. The drive over test in the video here is replicating an incident we had occur unintentionally that I talk about in a post here: http://sinistralrifleman.com/2012/04/06/cav-15-polymer-lower-receivers/



Link Posted: 3/18/2014 11:19:26 AM EDT
Not worth the risk. Nothing wrong with a tried & true aluminum receiver to warrant the trouble that polymer receivers usually cause.
Link Posted: 3/18/2014 11:46:52 AM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By warpig8654:
Not worth the risk. Nothing wrong with a tried & true aluminum receiver to warrant the trouble that polymer receivers usually cause.
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Please see the above video. Then run over your metal AR, and shoot it through the buffer tube and mag well with .223. Then report back.
Link Posted: 3/18/2014 11:52:58 AM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By 8afuzzball:
I see that OP has been talked into an aluminum lower.

Getting back to his original question about polymer lowers, I've seen recommendations for the JMT and Sabre SR-15.

Regardless of it being 80% or a finished lower, anyone else make a good polymer lower?

Note: I agree that aluminum is both proven and cheaper. I'm only considering the polymer for a .22 and I don't have a polymer lower yet.
View Quote

New Frontier Armory makes excellent polymer lowers, and they have a lifetime warranty. Just Google New Frontier Armory stress test, there at least 3 videos on YouTube. NFA was making their polymer lowers way before the Newtown shooting. After Newtown a lot of crap was made out polymer because of the ban threat, and because of it is a lot easier to crank production up on polymer than it is on aluminum lowers. NFA lowers are not the prettiest ones out there, the ATI Omni are the prettiest ones, but the NFA lowers have proven to be reliable. Unlike the NFA lowers, ATI polymer lowers are not reinforced in the rear takedown pin area and crack in that area. With that said, I am not a fan of the polymer parts in a complete NFA lower. I would buy them stripped and use a milspec LPK.
Link Posted: 3/18/2014 12:03:05 PM EDT
Originally Posted By shootertim:
I am about to start my 3rd build, and was thinking about going the polymer 80% route. Are there brands to steer clear of? I was planning on going with the polymer 80 brand.
View Quote



Link Posted: 3/18/2014 12:45:12 PM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By txcas:

New Frontier Armory makes excellent polymer lowers, and they have a lifetime warranty. Just Google New Frontier Armory stress test, there at least 3 videos on YouTube. NFA was making their polymer lowers way before the Newtown shooting. After Newtown a lot of crap was made out polymer because of the ban threat, and because of it is a lot easier to crank production up on polymer than it is on aluminum lowers. NFA lowers are not the prettiest ones out there, the ATI Omni are the prettiest ones, but the NFA lowers have proven to be reliable. Unlike the NFA lowers, ATI polymer lowers are not reinforced in the rear takedown pin area and crack in that area. With that said, I am not a fan of the polymer parts in a complete NFA lower. I would buy them stripped and use a milspec LPK.
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Originally Posted By txcas:
Originally Posted By 8afuzzball:
I see that OP has been talked into an aluminum lower.

Getting back to his original question about polymer lowers, I've seen recommendations for the JMT and Sabre SR-15.

Regardless of it being 80% or a finished lower, anyone else make a good polymer lower?

Note: I agree that aluminum is both proven and cheaper. I'm only considering the polymer for a .22 and I don't have a polymer lower yet.

New Frontier Armory makes excellent polymer lowers, and they have a lifetime warranty. Just Google New Frontier Armory stress test, there at least 3 videos on YouTube. NFA was making their polymer lowers way before the Newtown shooting. After Newtown a lot of crap was made out polymer because of the ban threat, and because of it is a lot easier to crank production up on polymer than it is on aluminum lowers. NFA lowers are not the prettiest ones out there, the ATI Omni are the prettiest ones, but the NFA lowers have proven to be reliable. Unlike the NFA lowers, ATI polymer lowers are not reinforced in the rear takedown pin area and crack in that area. With that said, I am not a fan of the polymer parts in a complete NFA lower. I would buy them stripped and use a milspec LPK.



not true I have an ATI Omni hybrid and it is reinforced with metal in the buffer tube and rear takedown pin area!
Link Posted: 3/18/2014 12:51:03 PM EDT
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Originally Posted By uniquesnd:



not true I have an ATI Omni hybrid and it is reinforced with metal in the buffer tube and rear takedown pin area!
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Originally Posted By uniquesnd:
Originally Posted By txcas:
Originally Posted By 8afuzzball:
I see that OP has been talked into an aluminum lower.

Getting back to his original question about polymer lowers, I've seen recommendations for the JMT and Sabre SR-15.

Regardless of it being 80% or a finished lower, anyone else make a good polymer lower?

Note: I agree that aluminum is both proven and cheaper. I'm only considering the polymer for a .22 and I don't have a polymer lower yet.

New Frontier Armory makes excellent polymer lowers, and they have a lifetime warranty. Just Google New Frontier Armory stress test, there at least 3 videos on YouTube. NFA was making their polymer lowers way before the Newtown shooting. After Newtown a lot of crap was made out polymer because of the ban threat, and because of it is a lot easier to crank production up on polymer than it is on aluminum lowers. NFA lowers are not the prettiest ones out there, the ATI Omni are the prettiest ones, but the NFA lowers have proven to be reliable. Unlike the NFA lowers, ATI polymer lowers are not reinforced in the rear takedown pin area and crack in that area. With that said, I am not a fan of the polymer parts in a complete NFA lower. I would buy them stripped and use a milspec LPK.



not true I have an ATI Omni hybrid and it is reinforced with metal in the buffer tube and rear takedown pin area!

They must have changed their design after the crack problems. The first generation of their polymer lowers did not have any metal and there were pictures right here about them cracking.
Link Posted: 3/18/2014 1:28:30 PM EDT
[Last Edit: 3/18/2014 1:31:44 PM EDT by ScoeyAz]
$50 Alm lowers - good to go.. buy a bunch.

Poly is cool.. its just not there yet and the technology is not there either.


Once you understand composites and high cycle fatigue.. you understand what alum in the pick of the day.
Ya sure a composite one could be made just as strong.... and would be better... but the materials are $1,000s of dollars.


Link Posted: 3/18/2014 2:26:30 PM EDT
[Last Edit: 3/18/2014 2:30:24 PM EDT by SinistralRifleman]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By ScoeyAz:
Poly is cool.. its just not there yet and the technology is not there either.


Once you understand composites and high cycle fatigue.. you understand what alum in the pick of the day.
Ya sure a composite one could be made just as strong.... and would be better... but the materials are $1,000s of dollars.

View Quote


Nonsense. The technology exists and has existed since 2003. It's as simple as not designing a plastic part to do the job the same way as an aluminum part. The technology is called the CAV-15 MKII. It takes advantage of plastic manufacturing technology without compromising durability by incorporating the buttstock, buffer tube, pistol grip, and trigger guard into the receiver. It eliminates the fail points of take down pin holes in polymer by using pins with the detents built in. It does not use 90 degree corners where possible as curved edges are stronger in plastic. Plastic can do the job incredibly well when applied appropriately

I personally have receivers with 10,000 rounds on them. Cavalry Arms had receivers with 50,000 rounds on them that were post sample machine guns. GWACS Armory (the current manufacturer) recently got a range gun back from Shooters World Phoenix for replacement. It had been on the range since 2003 and had 4 uppers shot to death on it. The only reason they sent it back is to get one with GWACS markings to reflect what they currently sell.

I've posted a video in this thread that shows a CAV-15 MKII undergoing things that would immediately disable an aluminum receiver because it would bend permanently rather than flex, yet people want to dismiss all polymer receivers as inferior from a construction stand point. The only sin the CAV-15 MKII can rightly be accused of is not having a telestock. If it did, it wouldn't work or have the same durability and resilience.


(note this is an old ad, and Cavalry Arms Corp since ceased operations and the CAV-15 MKII was sold to GWACS Armory)

I won't argue if people say a CAV-15 MKII doesnt have the features of modularity they want or the 13" LOP stock is too long. I will argue to death when people claim that a polymer receiver can't work just as well-and in some cases better than aluminum.
Link Posted: 3/18/2014 2:35:03 PM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By SinistralRifleman:


Nonsense. The technology exists and has existed since 2003. It's as simple as not designing a plastic part to do the job the same way as an aluminum part. The technology is called the CAV-15 MKII. It takes advantage of plastic manufacturing technology without compromising durability by incorporating the buttstock, buffer tube, pistol grip, and trigger guard into the receiver. It eliminates the fail points of take down pin holes in polymer by using pins with the detents built in. It does not use 90 degree corners where possible as curved edges are stronger in plastic. Plastic can do the job incredibly well when applied appropriately

I personally have receivers with 10,000 rounds on them. Cavalry Arms had receivers with 50,000 rounds on them that were post sample machine guns. GWACS Armory (the current manufacturer) recently got a range gun back from Shooters World Phoenix for replacement. It had been on the range since 2003 and had 4 uppers shot to death on it. The only reason they sent it back is to get one with GWACS markings to reflect what they currently sell.

I've posted a video in this thread that shows a CAV-15 MKII undergoing things that would immediately disable an aluminum receiver because it would bend permanently rather than flex, yet people want to dismiss all polymer receivers as inferior from a construction stand point. The only sin the CAV-15 MKII can rightly be accused of is not having a telestock. If it did, it wouldn't work or have the same durability and resilience.

http://sinistralrifleman.files.wordpress.com/2012/04/oleg-1.jpg
(note this is an old ad, and Cavalry Arms Corp since ceased operations and the CAV-15 MKII was sold to GWACS Armory)

I won't argue if people say a CAV-15 MKII doesnt have the features of modularity they want or the 13" LOP stock is too long. I will argue to death when people claim that a polymer receiver can't work just as well-and in some cases better than aluminum.
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By SinistralRifleman:
Originally Posted By ScoeyAz:
Poly is cool.. its just not there yet and the technology is not there either.


Once you understand composites and high cycle fatigue.. you understand what alum in the pick of the day.
Ya sure a composite one could be made just as strong.... and would be better... but the materials are $1,000s of dollars.



Nonsense. The technology exists and has existed since 2003. It's as simple as not designing a plastic part to do the job the same way as an aluminum part. The technology is called the CAV-15 MKII. It takes advantage of plastic manufacturing technology without compromising durability by incorporating the buttstock, buffer tube, pistol grip, and trigger guard into the receiver. It eliminates the fail points of take down pin holes in polymer by using pins with the detents built in. It does not use 90 degree corners where possible as curved edges are stronger in plastic. Plastic can do the job incredibly well when applied appropriately

I personally have receivers with 10,000 rounds on them. Cavalry Arms had receivers with 50,000 rounds on them that were post sample machine guns. GWACS Armory (the current manufacturer) recently got a range gun back from Shooters World Phoenix for replacement. It had been on the range since 2003 and had 4 uppers shot to death on it. The only reason they sent it back is to get one with GWACS markings to reflect what they currently sell.

I've posted a video in this thread that shows a CAV-15 MKII undergoing things that would immediately disable an aluminum receiver because it would bend permanently rather than flex, yet people want to dismiss all polymer receivers as inferior from a construction stand point. The only sin the CAV-15 MKII can rightly be accused of is not having a telestock. If it did, it wouldn't work or have the same durability and resilience.

http://sinistralrifleman.files.wordpress.com/2012/04/oleg-1.jpg
(note this is an old ad, and Cavalry Arms Corp since ceased operations and the CAV-15 MKII was sold to GWACS Armory)

I won't argue if people say a CAV-15 MKII doesnt have the features of modularity they want or the 13" LOP stock is too long. I will argue to death when people claim that a polymer receiver can't work just as well-and in some cases better than aluminum.


Per chance do you work for the new Cav Arms? Most are aware that Cav Arms receivers are the usual exception. However, when speaking of polymer receivers most are referring to the Plum Crazy, New Frontier, Ati, etc. Drive on.
Link Posted: 3/18/2014 4:58:57 PM EDT
I just got two stripped hybrid lowers from Tennessee Arms http://www.tnarmsco.com/receivers. These have brass parts molded into buffer tube ring and grip screw. For the most part they are not bad, but had some major fitting issues. It kinda amazes me in this day and age, people still can't get a mold to be more precise. The issue wasn't just trimming off the edges but somehow the front takedown holes are off slightly so the entire upper receiver is canted slightly to the left. There is a little step by right selector detent to push the upper to the left also. Very odd issue I must say. Ended up having to do quite a bit shaving to get the take down pin holes to line up.

Before people jump on me for building a poly lower, I was building a range queen to try to get my wife into shooting so durability wasn't the top concern. This is the least expensive way to get pink lower by a long shot. Plus it's a little lighter and not so "cold" to touch as metal so hopefully it's less scary to her.
Link Posted: 3/18/2014 5:14:10 PM EDT
I cant ever see myself buying a poly lower. ive had too many people I know run into issues with these things. seems much harder to break tabs and the like on aluminum
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