Why not Polymer?

[Fletch]

Disclaimer: I'm a total Greenhorn to ARs, but have plenty of experience with machinery through the years. Given the success and proven durability of Glocks, XD, etc, what's the big hangup with a polymer receiver for an AR? I've been researching a lot for my first build and most say something to the effect of: well it's okay for a plinker, for a cheap first rifle etc. I don't get it, because it seems the receiver just holds the fire control parts in place and would have no effect on the performance of the rest of the gun. It seems all the other parts would be infinitely more important in determining the quality and dependability of the rifle. One are of concern that seems to be a major sore spot is the threaded area where the buffer tube attaches. It would never occur to me that a thin aluminum tube would be ideal for use as some sort of lever whether it be threaded to another piece of aluminum or polymer. Either way it has it's limits and should hold up to it's intended use of taking recoil just fine.

I watched the NFA torture test and they threw it around, used it as a step up, and ran it over with an f150 without ill effects. Maybe it is an AR purist type thing like the 1911 or bust guys. It just seems to me that the polymer would hold up every bit as well to extreme use as aluminum if not better. I've got some polymer composite ramps for my vehicles that have worked great and are the only thing between me and a horrible crushing suffocating death every time I use them. Should I only "trust my life" to aluminum or pot metal ramps and use the polymer ones for working on the lawnmower and other things I could bench-press off when the "plastic" fails me? Because according to 95% of AR aficionados around the web it most certainly will at the most inopportune time.

 

[woody]

Polymer or Pot metal, your choice, just make sure it is Mil-Spec......

 

[Ken232]

Polymer mags do me well at the range but in some combat type enviroments (extreme heat or miserable cold) some have failed (Split seams or large running cracks) when dropped on concrete or pretty much any sufficently hard surface. I've had a couple split at the seams when shooting tactical enviroment type training( throwing Alot of lead downrange as fast as I can pull the trigger in copius amounts while moving hastily aka getting the hell out of dodge) but to be honest those were few and far between. Myself Metal Mags w/Green Followers have yet to do me wrong

 

[itsazonik]

I have about 10 polymer lowers. i have one on my 458 socom and one on my 338 spectre. my socom has hundreds of rounds through it and no problems. they are not made with the same polymer as mags. the mags are cheap. these hold up as well if not better than metal lowers in everything i have used them for. any time i find someone trying to get out from under one i always buy it. i keep them for all kinds of builds. i even used one on my 6.8SPC with a slide fire. went through almost 300 rounds in a very short time and it did great

 

[Fletch]

6.8 with a slide fire sounds like an expensive day at the range but a blast I'm sure. Good to hear your positive experience with polymer. I picked a great time to get the build an ar bug, but what the heck. I figure I will roll with the polymer receiver since the others are priced as if they were milled out of a block of gold.

 

[itsazonik]

for the price they are charging i can get 2 polymer lowers and build 2 at a time. it wasn't a cheap day at the range but i reload so at least i got all my brass back and started over. we stuck the slide fire on the 458 socom and put 7 rounds down range, that hurt.

 

[SAWMAN]

My "concern" is not that the lower is polymer basically. I am not a metallurgist or a polymer guru,just asking...what happens when a hard steel pins spins in polymer or visa versa. What is the wearability of polymer on metal or metal on polymer ??

On the mags...I'm with Ken. Metal and green has served me well in the past and I'm too damed old to change. --- SAWMAN

 

[itsazonik]

well my 223 with a polymer has a few thousand rounds through it and i have no problems. i do run these in all my ARs now though


http://www.midwayusa.com/product/52...-small-pin-154-stainless-steel?cm_vc=wishList

 

[Fletch]

My "concern" is not that the lower is polymer basically. I am not a metallurgist or a polymer guru,just asking...what happens when a hard steel pins spins in polymer or visa versa. What is the wearability of polymer on metal or metal on polymer ??

On the mags...I'm with Ken. Metal and green has served me well in the past and I'm too damed old to change. --- SAWMAN

Not sure as I am no metallurgist or polymer expert either, but I tend to default to the Glock and how well their marriage of polymer and metal seems to have stood the test of time and extreme use. Their polymer mags are battle tested as well. I have a cheap Winchester 1400 semi-auto shotgun. It's a nice soft shooter and hasn't failed me, but it pales in comparison to my Belgium made Browning A5s in fit, finish, and feel.

I find it ironic that the knock from serious shotgunners on the Winchester 1400 is that it's receiver is made of aluminum and thus cheap and won't be durable enough for serious everyday use. Yet in the AR world, the aluminum receiver is touted as the standard for durability and longevity. Maybe if I engrave some really cool graphics on the Winchester receiver, like a wicked looking spider or skull, it will be worthy of "betting my life on" or at the very least taking on an Argentinean dove hunt.

In all seriousness, I think the real advantage of aluminum was the weight and cost savings and it was considered an acceptable compromise. If polymer can take that weight and cost savings even further with equal or greater durability it seems like a natural evolutionary transition to me. Time will tell I suppose.

 

[Dwatts1984]

Personally I think it comes down to preference. There have been tons of torture tests on polymer lowers... and they seem to hold up well. Ive only had one Polymer lower and I can say it held up perfectly. If your point of use is just to shoot on occasion, the polymer will me or exceed you expectation. If your planning on going into battle, Im sure it would hold up, however I wouldn't place my life on the line for it. But again that's why I think its preference. I didn't have any fitment problems either.
***Just my opinion***

 

[FrankT]

I consider my NFA Lower My Glock of a rifle, used daily to protect your life the Glock is as polymer as the NFA...so there you go.

 

[Fletch]

Man, I pray that I never find myself in one of these bet your life situations that is going to require a firearm to run 10,000 jam free rounds an hour. Do you don't bet you life on a cheap gun guys do business with mexican drug cartells or something? I stick with the tried and true stategy of trying not to piss off dangerous people and not sleeping with other people's wives.

 

[itsazonik]

the only problem i ever came across with fitment was the take down pins. they were a little stiff using the polymer pins that came with some of mine. i changed them out and have never had a problem since.

 

[ksenter]

agreed, I hate the polymer pins in my NFA

 

[FrankT]

I bought some metal pins but have not replaced them yet, the fit is nice and the gun is for sale.

 

[Patoz]

I know the original question was about polymer receivers, but the thread progressed to include mags also. Here is a series of comparison test conducted by Magpul back in September, when a certain branch of the military prohibited their use.

In every case the PMAGS out preformed the USGI Aluminum mags. Magpul is biased of course, however, the test were do very fairly as the videos show.

http://www.magpul.com/video.html#M3Test7

So for those who don't like polymer mags, I have six aluminum Bushmaster 30 rnd. mags (same as USGI) I'll gladly swap even for your PMAGS. I prefer the black ones with windows, but the 20 rnd. ones are OK too. :lol:

 

[Gravity3694]

The reason why the USMC banned PMags is because the gen 2 mag is incompatible with their new M27 IAR. This is more HK's fault since they designed a rifle with a magwell that is dimensionally different. Magpul came back and fixed the issue with their gen 3 mag. The Army for a time appeared to have a ban in a poorly worded statement, but later clarified that they are ok. Some people speculate that the Army hates PMags because they sunk a good ammount of money into developing their own polymer mag which then morphed into just a tan follower for the USGI mag.

I've never bought into Magpuls ads and torture videos. In the five years I've owned and used AR-15s. I've yet to run any of my mags over with a truck, shoot them or do anything as abusive as Magpul does. The most I've done to "abuse" both types of mags is heavy range use and carbine class/training. The reality is that its extremely rare if at all these things will happen. I will admit that durability wise Pmags do trump USGI aluminum mags, but its quite disingenuous to discount USGI mags as junk compared to Pmags (as I've seen many do). Pmags are nice, but I'll take either and I won't get butt hurt if I'm stuck with aluminum.