I am trying to build my first ar and was wondering peoples thoughts on polymer carbon fiber lowers. I have read the threads about polymer lowers but does anyone have any experience with the carbon fiber reinforced? I was thinking about a lower from tegra arms. Is there a better one to look at? Any advice would be appreciated.

I just used a polymer 80 for my first pistol build. Took me less than 2 hours to complete and could do number 2 in less than an hour.  Everything fit perfect and is seems really tough.
This latest generation has a beefier thread boss where the buffer tube screws in, and uses a captured nut (not threaded into plastic) for the grip. Time will tell, but it seems like it would require
some serious abuse to break this thing.

I think polymer lowers have their place, if you are trying to build a light weight sporting gun then use one. If you want to build a home defense/shtf/serious rifle then there is no other option than to use an aluminum lower.

There is no practical reason to use a poly lower.  Aluminum is stronger and only slightly heavier and prices are virtually the same.  Why would you use an inferior product?

Yes, any one that is made of metal.

This, don't waste your money.

Naysayers said the same thing about poly pistols, now 90% of the hand gun market has poly lowers. If you're doing an 80% lower poly is easier and more than strong enough and better than some of the pot metal junk out there metal is no guarantee of quality.

Yeah, but how many photos do you see of polymer pistols like this....



More than strong enough? BULLSHIT!!!

The problem is that there has not been a significant redesign of the receiver to accommodate the different material.  Some "fix" it with inserts, but what's the point, really, of a plastic lower that costs more than a decent forged lower?

This. I bought some Anderson blem lowers for $42.33 each (including shipping) which I can't even find blems on. I don't care if a poly lower costs $5 because the lower is the least expensive thing in my builds at this point.



Aluminum lowers work and the weight savings, if any, between poly and aluminum is not worth IMHO.



Besides more people have had issues with poly lowers than aluminum lowers and a lot more of the later have been sold.

 

I am helping my brother in law mill an 80% Polymer Ares Armor. It is for his 10 year old daughter to learn on. It is very light. Thats the only good thing I have to say about it. You can tell how flimsy polymer is when you go after it with a milling machine. I see no way in the world I would EVER use polymer. Especially for a kid to shoot!  With good quality aluminum lowers out there, I dont see the advantages of polymer, all I see is that the negatives outweigh the positive. (lighter)

P.S. and its ungodly Pink . That alone makes my stomach turn

Get a good value forged aluminun lower and never look back.

Tony

I cant see any real advantage to using a poly lower,proper alum lowers are so cheap at the moment why bother with one..



the spotty track record the poly lowers have(some might be better than others)..not to mention this is your first build why risk having issues with a non std lower

Thanks for the feedback everyone. No purchase yet but I ll let you guys know

So i am still looking around and noticed that Bushmaster came out with a Carbon 15 line. Makes me wonder maybe there is something to these carbon fiber composite builds...I mean if the big guys are doing, it cant be garbage right?!

Unfortunately.... Wrong.

Google "broken Carbon 15".

this bud.

Well, after so many have posted about the quality/dependability of polymer lowers and you're still considering it then you've had your mind made up all along, and to that I say good luck Sir! Let us know how it works out for ya.

I don't care if a carbon lower was $10.

Never.

Ever.

Pay.

If you want a lightweight lower that isn't plastic/carbon/polymer and uses standard parts to install, look at a Mag Tactical or just a standard 6061 or 7075 type lower.

There are plenty of rifles being built which are properly finished and do not exhibit the traits of plastic/carbon/polymer lowers.  They stay together
They'll also be comfortable enough to learn on.  Just use a lightweight barrel, with or without a fixed front sight base, and a Magpul BUS rear, and a decent optic like a Vortex Strikefire2 or Sparc 2.

Even start looking at the S&W Sport M&P15 and doing minor modifications afterwards like a free-float rail, a new stock since they use milspec buffer tubes, and a brake or different flash hider.

You'll be better off in the long run with that type of gun.

I'll also mention that I am in the industry on a full time basis and I have worked for some manufacturers as an instructor and taught police officers how to service their duty guns so they don't have to bring them to me every time they want a new rail installed.

We do carry some carbon 15 rifles in our store and I've sold maybe 2 of them in 5.5 years simply due to Bushmaster's inability to stop production on that awful POS.

Avoid a carbon gun altogether OP.

Good luck.

This.

If you still decide to go with a cheap "carbon fiber" or polymer lower after everything you've read, you are being willfully ignorant, and there's nothing else we can do for you...

Welcome aboard. The fact is it is your money and time but as many before me have stated their opinions and facts that purchasing a poly/plastic/carbon fiber lower for the AR platform WOULD/IS a waste of Time and money. You asked our advice and it was given to you. Just got a feeling if you buy one you will be back here later posting a thread about this POS broke on me and how do I fix it? So we will end that now with a get an alum lower.

2 things should never be on your AR, plastic lowers and Lego's.

Yes.  That's sound reasoning.  Especially in AK.

There's a difference though those new polymer handguns were designed from the beginning to be polymer, AR lowered are not they are just a modified aluminium Reciever mold so weak points will be created because of the difference in materials strengths and weaknesses.

Check out James Madison tactical best poly lower I've seen

Why would a person pay $100 for a polymer lower(and still have to mill it) when they can get a billet lower for $130, or a forged for $60 bux.