Anyone been following these polymer lowers from Tennessee Arms?

[discreet]

With the exception of the Cav Arms lower (which I know has it's own share of haters), plastic lowers to this point haven't been a wildcard... they've all sucked.

It's the way forward, though, and whoever can make a reliable one should do well. Obviously the technology isn't ready for prime time, but some day it will be.

Huh? I was talking about MAG lowers. Polymer lowers at least are consistently crappy rather than being consistently non consistent. lmao.

[nova3930]

It's the way forward, though, and whoever can make a reliable one should do well. Obviously the technology isn't ready for prime time, but some day it will be.

I think you can come up with a successful design IF someone takes the time to properly engineer it instead of just taking the CAD file for a forged aluminum lower and making an injection mold out of it.

That said, I have yet to see a polymer lower that is properly engineered on the face, much less when you dig into the details..

[discreet]

I think you can come up with a successful design IF someone takes the time to properly engineer it instead of just taking the CAD file for a forged aluminum lower and making an injection mold out of it.

That said, I have yet to see a polymer lower that is properly engineered on the face, much less when you dig into the details..

LOL makes you wonder if Glock would be able to perfect it

[nova3930]

LOL makes you wonder if Glock would be able to perfect it

They might. They've been doing polymer long enough and they've got the resources to actually do the design work and test & eval. IMO I think to do it correctly would require the use of metallic reinforcement in strategic locations, primarily at the RE and possibly at the pistol grip attach point and the takedown pins. Maybe one day if I get a CAD model and some free time (the latter less likely than the former) I might run some FEA to play with some ideas...

[daveroberts]

well this is Dave.... the guy who owns Tennessee Arms Company

We had some initial issues that we are doing everything we can to fix. Rome wasnt built in a day and doing something that has never been done before is far from easy.

The reasons for having a polymer lower receiver are the exact same as the reasons for having a polymer lower on a pistol. There are significant weight savings and the material is much more resilient. There is zero reasons that the lower receiver needs to be metal. There are zero reasons for the upper receiver to be anything but metal.

The last post was about having metal reinforcement in the RE and pistol grip areas.. Its already been incorporated into our design and we have the patent filed for it. No other company will be able to run a threaded metallic insert in polymer once the patent issues. Until then we are having to suffer through having competition.

ar-15-lower-receiver-with-inserts-cut-aways(1).jpg

Polymer itself has some interesting properties that arent a concern when dealing with metal. The shrinkage rates vary according to the temperature of the injection material and the time of the shot. The greatest change is from the temperature of the injection mold and the cooling of the part after extracting it from the mold. That is where our initial issues were coming from. My personal rifle is the sixth one that was ever produced on our mold and everything works fine. A few dozen more into it we started seeing variation of about .02" in shrinkage variation in some places and .018" in others depending on the manufacturing process.

We have altered our mold tolerances to produce a part within mil-spec manufacturing tolerance using a predetermined process. We have our bugs worked out now. while we are constantly improving our process and product the main issues we were having have been resolved.

As for if people will accept a polymer lower industry wide is not really a concern. My concern is making a high quality part that is as tough and reliable as I can. I think I have done that. My receiver can be nearly crushed in a vice and still drop a mag free. The are also more rugged than a forged lower. They are capable of taking far more abuse and remaining within operational tolerance.

I understand the polymer lowers have gotten a bad rap... Im a shooter I get it. That wasnt my company or me. Im not going to allow a product like that to have my name on it.

If you ever have any questions, comments, or even criticism of my receivers please let me know.... I wont get butthurt..

Dave Roberts

[discreet]

I think many of us are skeptical anytime we hear claims of polymer being more rugged than metal. Magpul has proven their polymer mags are solid, but then again, those are mags not lowers. Time will tell to see how they stack up. Unfortunately it will be an uphill battle for you, especially convincing others, as all who have tried to this point have failed. I recommend getting a true SME like LAV or Haley to throw a beatdown on it and put it through the paces. I'm sure that alone will put minds at ease if it truly does pass the tests. At this point I don't think anything polymet would last one of lav's test, but then again... glock did with flying colors

Good luck with your endeavor. Hope you prove many of us wrong!

[burgeman]

Dave, did Pat receive his lowers and get them out for hard use?

Sent from my DROID RAZR using Tapatalk

[^Rb]

The last post was about having metal reinforcement in the RE and pistol grip areas.. Its already been incorporated into our design and we have the patent filed for it. No other company will be able to run a threaded metallic insert in polymer once the patent issues. Until then we are having to suffer through having competition.

ar-15-lower-receiver-with-inserts-cut-aways(1).jpg

This is the first I've seen this in a polymer lower and very cool.

Best of luck to you & your company.

[superstratjunky]

Dave have you done any mortaring testing? Any thoughts of scraping the AR & starting from scratch? How about doing away with the buffer tube on the lower & designing an all aluminum upper & poly lower? The problem is the back of receiver near the rear take down pin. That whole area needs to be strong, not just the BT threads. This is exactly why MagPul & FN did away with the BT. The recoil impulse on that area is to great for polymer.

[JusticeM4]

Dave, thanks for your reply. Its good to hear it straight from the "horse's mouth" as they say.

Good luck with your lowers. I think you are on the right track.

I read an article regarding polymer lowers that their weakest points is the Front Pivot Pin area and Receiver Extension area. If you can strengthen and reinforce those areas, you can eliminate most of the problems plaguing poly lowers.