80% Polymer AR-15 lowers

echo6mike · Feb 6, 2019

Looking at these currently, I see that Polymer80 has a new gen 3 of their AR-15 pattern out, wondering if that's going to be enough different from the 2nd gen to, well, make a difference.

Also wondering if there are other brands out there to look for that would be good, for a "before the f$cking MGA bans everything" build project.

And yes, I'd like to stick to polymer as I have neither the 1) skills nor 2) tools to work on a metal (aluminum or other) version. This would also probably be for a dedicated .22LR build.

Anyway, I don't see current chat about 80% AR lowers around MDS, so here I am!

SF

GuitarmanNick · Feb 6, 2019

Other than the flared magwell and a heavier buffer tube housing, the only difference that I see is the serial number strip. I like the idea of a heavier buffer tube housing if you plan to use it on rifle caliber uppers.

The G150 v2.0 that I built is waiting for a 9mm upper to compliment it.

echo6mike · Feb 6, 2019

So, looking at other brands, anyone know of these?

https://www.tnarmsco.com/80receiver-ar15-style-blanks/

Brass threads for the screws (buffer, grip), I like the idea...

East2West · Feb 12, 2019

You hear folks talk about these things failing with just normal use. But, has anyone ever really known or had one fail on them?

tony7815 · Mar 6, 2019

I have machined 3 80% polymer lowers. Two were built into 7.62x39 rifles and perform excellently, very accurate, each have close to 2000 rounds through them. I haven't decided what I want to build with the third lower. I used Polymer80 brand. Rather than use the screws provided to join the two halves of the jig, I drilled through for 4-40 screws and nuts. Also, instead of using the 3/8" twist drill to hog out the material for the fire control group, I used a 5/8 inch Forstner bit. This bit drills a flat bottom hole and allows for overlap drilling. The 0.625" hole is less than the 0.690" final width. The magazine well requires some filing and some filing was required to mate the upper and lower.

JimB · Mar 6, 2019

I have used Polymer80 and EP Armory. I beat mine and have had 0 issues.

marcus6576 · Mar 6, 2019

I have used 4 James Madison Tactical. I have had zero issues with 3 in 5.56 and 1 in 300 BLK. Easy to machine, no fit issues with mil-spec parts, and about 1000 rnds through each. Also, I used a 3/8 end mill in a drill press for the FCG, which is the proper tool for this. I have heard all the rumors that these can fail, haven't seen any pictures of this yet, YMMV.

Alphabrew · Mar 30, 2019

Any good deals on Poly80 lowers?

Kman · Mar 30, 2019

I have 2 New Frontier poly lowers. One not used yet...might do dedicated 22.
The other is 5.56 pistol with brace. Maybe 750 rounds with no issues. I'm not crazy about the little flexing I feel, but it works.

teratos · Mar 30, 2019

Why not do some aluminum lowers?

Sirex · Mar 30, 2019

I've been thinking about a few poly 80% lowers to build as .22s as well, with possible short term .223 or 7.62x39 use, or just keep the 80% lowers on hand as just in case items. Not sure which brand yet, still researching.

babalou · Mar 31, 2019

New Fromtier

Kman said:
I have 2 New Frontier poly lowers. One not used yet...might do dedicated 22.
The other is 5.56 pistol with brace. Maybe 750 rounds with no issues. I'm not crazy about the little flexing I feel, but it works.

Got a complete lower from joe bobs a couple years ago to build a cheapo AR15 and was able to back then for under $500. Works well does flex a little. Built for .223/5.56. Texas Precision Tactical complete upper 1:7 twist too.

babalou · Mar 31, 2019

80%

Kman said:
I have 2 New Frontier poly lowers. One not used yet...might do dedicated 22.
The other is 5.56 pistol with brace. Maybe 750 rounds with no issues. I'm not crazy about the little flexing I feel, but it works.

Were they 80% or complete or stripped? Thought they also made 80% polymer as well

babalou · Mar 31, 2019

Read of these

marcus6576 said:
I have used 4 James Madison Tactical. I have had zero issues with 3 in 5.56 and 1 in 300 BLK. Easy to machine, no fit issues with mil-spec parts, and about 1000 rnds through each. Also, I used a 3/8 end mill in a drill press for the FCG, which is the proper tool for this. I have heard all the rumors that these can fail, haven't seen any pictures of this yet, YMMV.

I read they are near or tops in a lot of 80% poll rankings

Kman · Mar 31, 2019

babalou said:
Were they 80% or complete or stripped? Thought they also made 80% polymer as well

One stripped and one complete.

MrRescuePack · Jul 8, 2019

I tried it

echo6mike said:
Looking at these currently, I see that Polymer80 has a new gen 3 of their AR-15 pattern out, wondering if that's going to be enough different from the 2nd gen to, well, make a difference.

Also wondering if there are other brands out there to look for that would be good, for a "before the f$cking MGA bans everything" build project.

And yes, I'd like to stick to polymer as I have neither the 1) skills nor 2) tools to work on a metal (aluminum or other) version. This would also probably be for a dedicated .22LR build.

Anyway, I don't see current chat about 80% AR lowers around MDS, so here I am!

SF

I tried the polymer and aluminum... polymer is a bit tricker in my opinion. If you go polymer make sure you receive all your parts because the bolt catch is a proprietary piece that standard lower parts kits won’t fit. Do the corners first when drilling the top and be mind full of how easy the trigger slot and safety hole can be off center. If you want to do aluminum I’d me more than happy to let you use my tools.

GSXR750 · Sep 11, 2019

i'm a big fan of the polymer80 lowers, easy to mill and zero issues/functioning.

GSXR750 · Sep 20, 2019

oh, and to add, if you are using an inexpensive harbor freight drill press and x/y vice, then polymer is the only way to go because there is some slop in those items and it's not as precise unless you can go slow and cut through polymer material.

80% Polymer AR-15 lowers

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