Polymer AR lower receiver.

[creophus]

Check these out.
http://www.auctionarms.com/search/displayitem.cfm?ItemNum=9528586&printitem=1

I've been reading up on these and wanted to get your opinions. They make the lower receiver from a polymer/plastic.

I've heard lots of jokes about the name, but I suppose I'll hear more in this thread to.

I work with a guy that knows a guy who just bought one of these. He should get it tomorrow and hopefully he'll let me take a look at it and maybe even fire it.

[BigSlick]

You knew that was coming sooner or later.

The real story is the lowers are pieces originally intended for the Glock Carbine, but the uppers weren't ready for the SHOT Show, so they let a few go. :rofl:

I cain't wait for a chrome lined tennifer coated M4gery upper

[creophus]

You knew that was coming sooner or later.

The real story is the lowers are pieces originally intended for the Glock Carbine, but the uppers weren't ready for the SHOT Show, so they let a few go. :rofl:

I cain't wait for a chrome lined tennifer coated M4gery upper
If only that's what happened! I'm curious if these things will hold up.

[MONTEGOD7SS]

Just the flash on the front from molding and never even being sanded off would be enough for me to say nooooo thank you. You can get mil spec regular lowers for $10 cheaper.

[creophus]

Just the flash on the front from molding and never even being sanded off would be enough for me to say nooooo thank you. You can get mil spec regular lowers for $10 cheaper.
I understand about the flashing. However those are COMPLETE lowers for that price. They even have the collapsible buttstock.

[Mogollon]

I have a really lightweight AR I built on a Cavalry Arms lower. Very satisfied with it. I had a new lightweight Israeli surplus M-16 barrel made by SAK, so it weighs about 6 pounds.
http://www.cavalryarms.com/

[MONTEGOD7SS]

Ah, didn't think about it being the WHOLE lower for $99. Might be a good beater for something like BGGB did for a hunting rifle. If that's the case, it might be light enough to carry all day and not feel like you're carrying a battle rifle.

[creophus]

I have a really lightweight AR I built on a Cavalry Arms lower. Very satisfied with it. I had a new lightweight Israeli surplus M-16 barrel made by SAK, so it weighs about 6 pounds.
http://www.cavalryarms.com/

Now their lowers are slightly different in regards to dimensions right?

Ah, didn't think about it being the WHOLE lower for $99. Might be a good beater for something like BGGB did for a hunting rifle. If that's the case, it might be light enough to carry all day and not feel like you're carrying a battle rifle.

I certainly like the price, I just want to make sure they hold up.

[Mogollon]

The Cav Arms lowers use a carbine spring and buffer, otherwise all standard lower internals fit fine

[Rollis]

BushMaster has a polymore lower, also I beleve Armalite doe's too. I, have heard second hand that the front pin area can become worn if it is disasembled to often on the Armalight, don't know if it true or not.

[cohutt]

I've shot and handled a bushy carbon 15- nice enough but it didn't inspire me to go buy one. Even though i doubt i could wear one out I'll stick with the traditional

[Rollis]

My S&W AR15_22 is all polimer so I'll be finding out about it in soon enugh time.

[grendelbane]

I see that they are working on a California compliant model. Which tells me that they think the front pin will hold up to a lot of use.

I am keeping an open mind on this one. I still have people tell me that my Cav Arms won't hold up, even though it has fired thousands of rounds of both .45 ACP and 5.56.

The price is right. Not much $$$ heartbreak if you buy one, and it doesn't suit you, or falls apart.

[Rollis]

Seem's to me that a metal insert for the pin holes would eliminat any problems.

[Brass Nazi]

PlumCrazy? They must be Mopar guys.

[MONTEGOD7SS]

Everybody has their burdens they have to carry, BN. :)

[BIGGUNGOBOOM]

hey, what them MOPAR comments. some people happen to love MOPAR !!!!!!!!!!!:) :)

[creophus]

Well hopefully I'll get to shoot this thing soon. The guy will let me know when it comes in. I'll try to do a full write up.

[creophus]

Well guys the polymer lowers are in and so far they look good. I'll head to the range ASAP and give all kinds of feedback.

Please post up any questions you might have. It would be better to get them now while I have the thing in my posession than get the questions later.

[BigSlick]

How do the polymer internals look and how's the fit to the upper ? any slop in it ? Not bad at all for $100

[creophus]

So far this thing is looking rock solid. I haven't had much chance to mess with it yet. I've only had the opportunity to dry fire it. Plastic trigger felt just as heavy as the standard metal AR trigger. That hammer gave the firing pin enough of a whack to wake everyone up this morning. It probably makes up for mass with velocity.

All of the internals are polymer including the hammer (wrap your mind around that), springs not withstanding of course. The buffer tube (this one has a collapsible stock) is metal and so is the castle nut.

You wouldn't know it was polymer until you touched it.

What's the best way to test this thing? I have the complete rifle as the guy gave me a RRA upper to go with it. I don't think shooting for groups is a test of the lower. I certainly don't want to break this thing as it doesn't belong to me. I'm thinking rapid fire drills would be the biggest test of the lower. Also an endurance test by putting 1k or more rounds would be a good test but I just don't have that kind of factory ammo stocked up.

I'm not comfortable putting my reloads through someone else's gun.

[MONTEGOD7SS]

How about the mag well? Do mags seem to be held as securely as an aluminum lower?

[creophus]

Gonna test that out. I have a Colt Mag, C Products Mags and PMags that I'll test for function. I'm wondering if they will drop free also.

[BoltNut]

This is why being friends with shooters always pays off...guess who gets to help Creo with his research?! :-D

[creophus]

Word!

[creophus]

Ok, so I have two rifles built on plumcrazy lowers and one built on a "mil-spec" GSE lower. I have a 30 rd. colt magazine, a 30 rd. CP Products magazine, a 20 rd. PMag magazine, and an "Atchisson" .22lr conversion magazine.

I want to see if the magazines will drop freely from the rifles. First I try them empty and then I try them loaded.


GSE "MilSpec" AR

Colt Magazine drops free
CP Products magazine drops free
PMag Magazine drops free
.22lr conversion magazine drops free*

Plumcrazy AR1

Colt Magazine drops free
CP Products magazine drops free
PMag does NOT drop free
.22lr conversion magazine drops free*

Plumcrazy AR2

Colt Magazine drops free
CP Products magazine drops free
PMag does NOT drop free
.22lr conversion magazine drops free*

I then tried the 20 round PMag full of ammo and there are no changes to the results.

I thought of doing more testing with full magazines but decided against it. Empty magazines are the ones more likely to be dropped from the gun rather than full ones.


I have yet to fire these things so I can't speak on that. Let me know what you guys think. I'll do a full review when this is all done.

[creophus]

Plumcrazy lowers allow for the safety to be manipulated whether the hammer is back or not.
Bottom of trigger gaurd is not removable or able to be opened
Bottom of trigger gaurd is "hour glass" shapped.
Trigger pull feels normal AR heavy.
Take down pins feel "wobbly", but slide in and out.
Take down pins ar plastic.
Upper to lower fit is tight. Seperating the two takes a bit of force.
The only metal on this lower is either a spring or the buffer tube and castle nut.
EVERYTHING else is plastic.

[Bultx1215]

I would bet the reason the Pmags didn't drop is due to friction, plain and simple. Plastic to contact wouldn't slide as easily as plastic to metal.

[creophus]

That's probably true. According to some Pmags often won't drop free from other lowers. That's probably a ploy by Magpul to get you to buy their magpulls.

[creophus]

How do the polymer internals look and how's the fit to the upper ? any slop in it ? Not bad at all for $100
To answer your question more specifically Slick, the internals look just like the metals ones...only plastic.

The plastic hammer appears a little bigger. The upper to lower fit is TIGHT. When the pins are pulled it takes a bit of effort to get the things to seperate. The pins are tight going in and coming out.

[2slow]

Can you swap out all the plastic trigger parts with a standard parts kit?

[creophus]

Can you swap out all the plastic trigger parts with a standard parts kit?
Not sure. I've heard that metal parts might tear up the internals.

[2slow]

Not sure. I've heard that metal parts might tear up the internals.
That's a shame. I think it would make a good light weight varmint rig with a better trigger.

[creophus]

Well we went shot them yesterday. I noticed the guns did not feel light weight. Even though the polymer lower weighs less the uppers and scopes still make a hefty feeling rifle. We had a heavy barrel and an M4 contour barrel on them.

The internals held up just fine. I had two issues which I *think* are magazine related. I switched to the PMag and it went away. I think it was either my CProducts or the Colt Mag that caused a double feed and the bolt being held open with an unfired round sitting on top (not inside) of the magazine. I shot slow from the bench and fast off hand.

The biggest difference between the rifles were the scopes. I tried not to make the shooting experience about scopes but lowers. The lowers never got hot nor did they show any signs of wear.

This was far from a torture test as we only fired about 30 rounds through each one. We didn't have much factory ammo on hand (no reloads in someone else's gun).

We used a Atchisson 22lr kit after shooting .223 and did NOT clean the chamber and the thing got stuck when we tried to remove it. As a result we could only test it on one of the rifles. However, the kit worked 100%. That AR became the heaviest .22lr I ever fired. No recoil, just noise and a hole in the paper let you know the round went off.

My only concern about these rifles are the plastic take down pins. They didn't feel as tight when I began firing. I'll see how they feel when I take down the rifles to clean them.


BoltNut what do you think?

[BoltNut]

I'd basically say the same thing. I was a little surprized at the wieght of those guns, especially since they were "shorties." Good thing the poly doesn't wiegh anything, otherwise, I'm not sure if I could have kept the 10 rounds offhand on the paper. My impressions are far more limited, since I know so little about what to expect from AR's in general...but I did like them. I thought the triggers were nice, with a crisp break and very little travel. I also tested the "safe" a couple times, just to see if it worked, and if the trigger flexed against it when engaged...nothing. It worked as advertised. I'm not a big fan of how short the adjustable rear stocks are, but I compensated just fine...if I was building one of my own, I'd probably get a Kick-Eezz Pad to add on to it for some extra length. The scopes were worlds apart, but like Creo said, we weren't there for that aspect of the game. The bench rest position with the Simmonds scope had me painting about a 3-4 inch group (if that) with 20 rounds. I figured it would be the same thing out to however far I wanted to try it...very smooth and fun.

Overall...I don't see any issues with it, but again, I'm kinda retarted in this arena, so listen to Creo over anything I say.

[BigSlick]

Interesting about the rimfire bolt getting stuck.

I used to have an old factory Colt .22 LR conversion that stuck the first couple times I used it, then I soaked it good in some Kroil and the problem went away with a couple more range trips.

But, do you think the polymer lowers are worth the $$ from an initial impression ?

All sounds pretty good except the take down pins.

Did you try any 20 round mags with em ?

[creophus]

Interesting about the rimfire bolt getting stuck.

I used to have an old factory Colt .22 LR conversion that stuck the first couple times I used it, then I soaked it good in some Kroil and the problem went away with a couple more range trips.

But, do you think the polymer lowers are worth the $$ from an initial impression ?

All sounds pretty good except the take down pins.

Did you try any 20 round mags with em ?
Are they worth it? --Yes, absolutely.

I'm not sure if the take down pins will be an issue, but as I already stated, that's the area that I'm looking at first and foremost as being an issue. Again, the upper to lower fit is quite tight and I found myself having to put considerable force to seperate the two when just the rear pin was removed. I didn't want to stress the front pin when doing so. There was a temptation to bounce the thing on my knee, but I refrained as that would have been excessive and could have led to damaging something. This will take some getting used to if you have any experience with metal lowers.

The PMag that I tried is a 20 rounder. I loaded it up all the way since it was brand new and I wanted to test it also.

I wanted to see if that bolt was gonna chew on the plastic hammer but there wasn't so much as a scratch on the hammer or any other part in that lower.

BoltNut noticed one of his mags fit loosely in the gun. It had a bit of wobble to it, but from what I can tell it ran fine. He also is correct about trying out the safety. Typically I don't use them. When we switched rifles he left his on safe and sure enough, that trigger didn't budge when I tried to fire it. If I recall the metal lowers move slightly even when the safety is engaged.

I also noted that the Colt and CProducts mag didn't drop free after firing a few rounds. Could it be they were dirty? I have no idea at this point.

Keep the questions coming as there's probably a lot that I'm leaving out.

[BigSlick]

As far as mags dropping free, the Colt mags (at least at one point) used to be mfg by OKay and I think Parsons. Happen to have any of either on hand to try out to see if you get similar results ?

Not sure about the dropping free, but I would certainly load a mag and check the dimensions of loaded vs unloaded and compare those to a mag that does drop free. It may not tell you anything except how those specific mags measure when loaded, but if the ones that do drop free measure smaller, that could be a part of it.

More likely is the mag catch is in a slightly different spot from one mag to the next. As you know, some mags have more of a 'ledge' than others, so that might be where they are hanging up. You could always mark the mags that don't drop out to see where they are making contact and see if BN's mag is any different.

As far as bouncing the lower to get the pins in and out, ya gotta use it sometime, so it might as well be now ;) I'd really be more interested to know if the pins get whacked by opening or swapping uppers cause no matter how gingerly you handle it, if they ain't gonna hold up it's gonna show up sooner or later.

[creophus]

As far as bouncing the lower to get the pins in and out, ya gotta use it sometime, so it might as well be now ;) I'd really be more interested to know if the pins get whacked by opening or swapping uppers cause no matter how gingerly you handle it, if they ain't gonna hold up it's gonna show up sooner or later.
Nah, I gotta get these things back to their owner in one piece! :)