Call it crazy, but ET Arms has decided to dive headlong into the wild world of polymer AR-style rifles with its weight-saving budget-friendly PlumCrazy Gen II polymer upper and lower guns. On the outside, they have a fairly traditional AR-15 vibe, if you look past the PlumCrazy logo at least. But these rifles take the idea of polymer-based guns to a new level.

Honestly, you have to appreciate ET Arms’ swagger, because there is a genuine level of crazy confidence that it put into the PlumCrazy rifle. The upper and lower are polymer, which is pretty darn unique all on its own. But nearly all the guts inside these ARs are made of polymer as well.

Given the low price point and attractive uniqueness of the PlumCrazy, I decided to snatch on for some testing over the winter. The results? Well, they were interesting.

Table of Contents

Video Review
A Polymer AR Rifle?
Specs & Features
Range Testing & Accuracy
Pros & Cons
Final Thoughts

Video Review

A Polymer AR Rifle?

ET Arms out of Lake Havasu City, Arizona, has already made a name for itself by pushing the boundaries of polymer lower receivers, but the full PlumCrazy Gen II rifle tapped the plastic vein a bit deeper with the addition of a nearly complete polymer upper receiver

ET Arms Plum Crazy Polymer AR-15 Rifle
One of the original dreams behind the AR platform was a light and easy-to-wield modern rifle. (Photo: Paul Peterson/

From the takedown pins and magazine release to the hammer, trigger, sear system, and safety, the gun boasts close to the maximum amount of polymer you can stuff into a rifle while keeping it a functioning firearm. Still, calling it polymer is a bit misleading. These rifles aren’t the byproduct of used water bottles. 

Major parts like the bolt, barrel, forward hand rail, and a few other impact-based features are still made from metal. But the lower actually uses a glass-filled nylon-6 material. For my test gun, I found the tolerances to be quite tight-fitting between the upper and lower. 

In a way, you could almost see this as a completist’s attempt to further Eugene Stoner’s original venture to create lightweight but modern rifles with more polymer and space-age materials that kick-started the original ArmaLite AR-15. 

Specs & Features


ET Arms Plum Crazy Polymer AR-15 Rifle
The upper and lower receiver are polymer, but the same is true for many of the internal parts like the hammer. (Photo: Paul Peterson/

From a form and function perspective, the PlumCrazy varies only slightly from your general AR-15 design. The controls (magazine release, trigger, safety lever, bolt catch, charging handle, etc.) remain the same. 

The charging handle slides directly into the rear of the upper receiver. Normally, there is a cutout inside the upper portion of the receiver that you have to slide the charging handle into. That seats it in its track before inserting the bolt-carrier group.

The polymer is a glass-filled nylon-6 material. I’ve added a photo of the major metal parts below. Most of the other metal inside the gun is either small screws or springs. But the amount of polymer is notable in the weight, and you can feel it in the handling of the gun. 

ET Arms Plum Crazy Polymer AR-15 Rifle
A small group of parts maintain the standard metal constriction. From top left to bottom right, these include the ejection-port cover, forward handguard, bolt stop/release, buffer and spring, bolt and charging handle, and – obviously – the barrel and flash hider. (Photo: Paul Peterson/
ET Arms Plum Crazy Polymer AR-15 Rifle
The trigger, on the other hand, is also polymer. Note the bowed trigger guard, which is a nice feature in my humble opinion. (Photo: Paul Peterson/

Here is a general summery of the specs for the PlumCrazy Gen II rifle:

Caliber: 5.56 marked barrel (“multi-cal” marked lower receiver)
Rifling: 1/8 twist
Barrel Length: 16 inches (17.6 with A2 flash hider)
Weight: 5.7 pounds
Trigger Pull: 4.3 pounds (10-pull average) 
Handguard: 10-inch M-LOK
Upper Rail: 16-inch Picatinny

ET Arms Plum Crazy Polymer AR-15 Rifle
The 10-inch M-LOK handguard is a fine addition for accessories while maintaining a lightweight feel.  (Photo: Paul Peterson/

The pistol grip and A2 flash hider are your standard AR affair. I like both well enough to be honest. What surprised me in a rifle that weighs less than 6 pounds was the very low felt recoil. The gun also came with a 60-round ATI Schmeisser magazine, and I didn’t note any issues running it over several range visits.

ET Arms Plum Crazy Polymer AR-15 Rifle
The gun comes with what is called a “mil-spec” M4-style six-position stock. Mil-spec is a term tossed around a lot, but I found this one to be less than ideal. At the price, however, you can swap it out for something nicer with little added cost. (Photo: Paul Peterson/
ET Arms Plum Crazy Polymer AR-15 Rifle
I am actually a fan of the original AR-style grip. It just has always felt good in my hand and lends itself to accurate shooting because you can adjust your grip around it. (Photo: Paul Peterson/
ET Arms Plum Crazy Polymer AR-15 Rifle
I opted to add a fixed Magpul carbine stock for around $20 over the recoil tube since it accepted mil-spec sizes. (Photo: Paul Peterson/

The buffer tube, hammer, trigger, and sear are all polymer. That buffer tube is mil-spec in size with a carbine-length spring, but it is also permanently fixed. Do not attempt to remove it or adjust the factory-set castle nut. While the manual claims the adjustable six-position M4-style stock is mil-spec, I found it to be rather flimsy, and it didn’t always hold its locked position without some fidgeting. At the price, for a few dollars, you can just slap on a different stock. I opted for a Magpul carbine fixed stock and have no regrets. 

ET Arms Plum Crazy Polymer AR-15 Rifle
There is plenty of room for attachments. I really dig the Magpul grip panels (top left) and the A2-style flash suppressor is fine by my book. The gun also comes with ambi one-point sling mounts and a set of serviceable backup iron sights. (Photo: Paul Peterson/

With the number of polymer internals, the actual manual uses the term “lubrication free” for the lower parts kit. It also says to add lubrication to moving parts. So, take that for what it is, but I have found that cleaning and maintenance are basically the same as your standard AR-15. 

ET Arms Plum Crazy Polymer AR-15 Rifle
I do have to drop some points for the trigger. It’s clunky, but it’s not that clunky. My bigger issue is the all-polymer construction and feel of the trigger is just not on par with most mil-spec metal trigger/hammer assemblies. It’s a win in that it proves you can make these parts out of polymer, but I would prefer they were more hardened metal regardless. (Photo: Paul Peterson/

You can notice the difference between the plastic trigger and safety when compared to metal mil-spec alternatives. Interestingly, the “safety-first” trigger also allows you to activate the safety even when the hammer is not cocked, and that diverges from standard AR safety/selector levers. The trigger reset is positive and audible. I kind of wish it was just a mil-spec metal trigger/hammer assembly because it is a very minimal weight savings to use polymer. The system works and offers a close-to-mil-spec pull for the trigger itself. 

Range Testing & Accuracy


ET Arms Plum Crazy Polymer AR-15 Rifle
The upper Picatinny rail offers plenty of space for optics, and I chose to add a Primary Arms 2.5x32 etched optic that has served well for my needs. (Photo: Paul Peterson/

The PlumCrazy Gen II comes with a note that you should allow 100-150 rounds for the “break-in” period. I have not found that to be necessary. I’m now sitting at north of 650+ rounds that are a wide mix of factory-loaded options. Handloads are not recommended, and I would caution against trying to use anything that blows past normal 5.56 NATO specs as the upper is still a polymer material.

For my first outing, this gun had a rude Wisconsin range day that was snowy and 15-20 degrees for most of the shooting. There was no cracking or failures inside the gun. I did notice that some of the lacquered steel-case ammo chambered a bit sluggish, but that vanished after a few magazines and for my future shooting trips.

ET Arms Plum Crazy Polymer AR-15 Rifle
Here’s how the range looked after some diligent shoveling before the first test of this rifle. (Photo: Paul Peterson/

Overall accuracy was within 1 MOA, and I ran a few drills you can see below for accuracy and controllability. In fact, I neglected to Loctite my 2.5x32 Primary Arms optic before first hitting the range because I was in a bit of the rush. That was easily solved but ruined my initial zero, and the groups below were actually shot with a Kentucky windage holding a few inches to the right of the targets.

ET Arms Plum Crazy Polymer AR-15 Rifle
I did have to work with an imperfect zero, but with a Kentucky hold, the gun did quite well at my 50-yard testing. The top left is a full 30-round magazine off a rest. Top right is off a bag with 30 rounds at the same 50-yard distance. Bottom left is a slow-fire standing target and bottom right is a more rapid fire standing at the same 50-yard distance. (Photo: Paul Peterson/

Suffice it to say, the gun shoots fine for anything I expect out of a standard AR. Reliability has been solid between range trips that varied from 15 to 85 degrees with rain and snow just to add some spice to the testing. That testing included Wolf and Tula 55-grain steel-cased ammo, Federal 55-grain .223 American Eagle, Winchester 5.56 M855 “Green Tip,” and 77-grain Federal Gold Medal match-grade ammo. 

AR Mags
I tested a variety of ammo and magazines without a noted issue other than some sluggish chambering in 15-degree weather with steel-case ammo in the first 100 rounds. (Photo: Paul Peterson/

Overall, I like the standard AR grip, but I did not like the included stock. That cost $20 to replace, so no big complaints given the cost of the rifle. The overall balance is also surprisingly nice, and recoil is soft and controllable. For the price, I liked how it felt and shot.

ET Arms Plum Crazy Polymer AR-15 Rifle
The polymer upper and lower didn’t seem to impact overall performance for me, but I did not personally like the trigger as much as a standard, metal mil-spec option. (Photo: Paul Peterson/

My biggest complaint is the trigger. It’s not heavy or overly clunky at 4.3 pounds. I did notice one issue with it failing to reset while shooting twice early in my testing, and I question the overall merits of making the entire trigger assembly polymer. I love the ambition, but I would prefer a mil-spec metal trigger just because it is predictable, functional, affordable, and weighs just a slight bit more for a rock-solid, proven trigger system.

Pros & Cons


  • Affordable AR-15 option
  • Lightweight
  • Reliable
  • Soft recoil
  • 5.56 chambering
  • Interesting polymer design
  • Mil-spec buffer-tube size
  • Runs various ammo and mags well
  • Fairly light trigger
  • Easy to clean and maintain
  • Widened trigger guard
  • Metal parts where it counts the most
  • Just fun to shoot


  • Fixed buffer tube
  • Not built for impact/abusive uses
  • Polymer trigger system isn’t my favorite
  • Original stock seemed flimsy, but it was easy and cheap to change
  • Safety is somewhat stiff even after 650+ rounds

Final Thoughts


ET Arms Plum Crazy Polymer AR-15 Rifle
For the price, I have little to complain about. But perhaps the best part is that this is a very unique and fun AR-style rifle to shoot. In a world filled with options when it comes to AR-15s, that’s something worth appreciating in my book. (Photo: Paul Peterson/

Look, you gotta take this gun for what it is on a certain level. It is not a Colt, FN, or Knight’s Armament military-contract rifle built to take a flying kick off a cliff above jagged rocks at a passing Scud missile. I also wouldn’t really want to try and buttstroke anyone with a rifle that has a polymer tube, but the PlumCrazy doesn’t pretend to be the world’s toughest AR.

It does make an interesting argument about just how far Eugene Stoner’s dream of a lightweight, reliable, magazine-fed modern rifle can go when it comes to space-age polymer. I think that merits a tip of the hat. 

Plus, at over 650 rounds reliably fed with a low price point, I can’t help but find this to be an interesting option for the casual AR shooter or someone who wants to add a truly unique AR-15 to their collection. I, for one, have done exactly that with my own cash. So far, I can’t say I have any regrets. 

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