Editor’s Note: The SureFire Institute’s Polymer Lower is not affiliated with the SureFire that makes illumination devices and suppressors. This product debuted a few years ago and the SureFire Institute, a separate company, appears to no longer exist.

I know what you are thinking – “SureFire Polymer Lower?”. Normally there is some healthy skepticism and recurring examples of polymer AR lowers being destroyed due to catastrophic failures. Apparently SureFire Institute had some AR-15 lowers made for them. The SureFire Institute polymer lower has components you would not consider, is made of polymer!

SureFire Institute Polymer Lower

During SHOT Show, back in January, I went into Ventura Munitions to exercise some freedom. While filling out a 4473 on one of their glass counters, I happened to notice a polymer lower with an interesting engraving. “SFI”. It was the font and the words “SUREFIRE INSTITUTE” molded into the polymer lower receiver.

I looked up from the counter and asked Nick of Ventura Munitions (great guy with a great name) if I could take a look at the SureFire Institute polymer lower that had a shocking price tag of just $89.00. No, this was not a stripped receiver for $89.00 but a complete lower as you see in the photo above and below. Sold, I’ll take as many as you got. Unfortunately, this was the last one in their store.

Now according to Nick of Ventura Munitions, this lower receiver was not made by SureFire the flashlight company. SureFire Institute was once affiliated with the SureFire flashlight company but they have gone their separate ways.

Immediately upon holding the SureFire Institute polymer lower something obvious jumped out at me. This entire gun is plastic. The only metal in the receiver are the following:

1. Takedown pin detents and springs
2. Hammer/Trigger pins and springs
3. Bolt catch, spring, & roll pin
4. Magazine catch spring
5. Pistol grip screw
6. Buffer, buffer spring
7. Buffer detent and spring
8. Castle nut
9. Receiver end plate

Notice anything odd about that list? The buffer tube is polymer!! Frightening. When I asked Nick about the polymer buffer tube he said not to swap any components out of the SureFire Institute polymer lower like the buffer tube or trigger. In fact, the lower is actually a U.S. Arms Manufacturing Patriot-15 that was OEM for the SureFire Institute. To make matters worse, the buffer tube is commercial spec.

Oh, it does not just stop there. Follow along with me as we continue this tour of things that probably should not be made of polymer on an AR-15 lower, besides the obvious (I am talking about the lower itself). How do you feel about polymer takedown pins? Yeah, I feel the same way. “But, why?”. To save an ounce or so?

Well, it doesn’t stop there, U.S. Arms Manufacturing went all the way. The safety selector, trigger, and mag catch are all polymer.

 

But that’s crazy Nick they couldn’t possibly keep going, could they? Oh yes, good reader, they can and did. Let’s make the trigger assembly polymer as well as the hammer!

How about a polymer mag catch? LOL

According to Classic Firearms, the “nanocomposite reduces felt recoil”

The proprietary lightweight nanocomposite construction of the SFI-15 lower receiver provides a superior strength to weight ratio. Our nanocomposite material also processes the kinetic energy created by the firing process in a much more efficient manner, producing less “felt recoil” compared to the traditional aluminum alternative. Combined with our patent pending SureSafe™ Fire Control System and you have the lightest and safest AR-15 / M4 / Variant rifle platform available anywhere in the world.

I am not entirely sure how the material can reduce physics like recoil.

It’s Not All Bad

The SureFire Institute polymer lower is not all bad. For starters, it is inexpensive for a completely built lower receiver. Add to the fact that it is rather lightweight. As is without a stock, the SureFire Institute polymer lower weighs just 506 grams or 17.8 ounces (1.1 lbs). That is not bad.

You may have noticed that the Ventura Munitions photo, posted earlier, depicts a different pistol grip. It came with a “USA MADE” pistol grip like the one you see in the Ventura Munitions photo. It looks like a bootleg of a CAA pistol grip. So I replaced it with a Magpul grip instead.

Another interesting feature about the SureFire Institute polymer lower is the SureSafe fire control system. You can flip the safety on even when the hammer is down.

Here is what Gulf Tactical had to say about it on their website.

SureFire Institute set out to overhaul the known weaknesses that exist with the current AR-15 / M4 / Variant rifle platform – most notably, the fire control group. SFI completely redesigned and upgraded the safety features of the milspec trigger mechanism, including added safety and tactical advantages not found on any other fire control group available for these platforms. The SureSafe™ FCS is the most feature-packed fire control system ever designed that will drop into the milspec lower receiver.

Traditionally, the safety selector switch on these weapons could only be engaged if the trigger is in the “fire” position. This has been the case because of small deficiencies in the design, and the mechanical limitation of the components. But not any more – SureSafe™ is designed to allow the safety selector switch to be engaged at any time, no matter the position of the hammer. This unique feature virtually eliminates the possibility of accidental discharges of the weapon system, as engaging the safety will now prohibit the hammer from moving forward, even in the event of a malfunction or transition.

Another innovative feature of the SureSafe™ FCS is the ability to charge the weapon system while in the “safe” position. The enhanced mechanism also offers a smooth trigger press with minimal creep, and a crisp break and reset – all of which makes the Patent Pending SureSafe™ Fire Control System truly built with the operator in mind, and unlike anything available on the market today.

According to an H&K representative, the HK416 trigger/safety selector functions like this. I do like this tan version of the SureFire Institute polymer lower. I wonder if it was molded in this color or if it was Cerakoted?

 Final Thoughts

I have only briefly shot the SureFire Institute polymer lower and found it to be adequate. According to Nick, he relayed some information that the SureFire Institute shared with him about their polymer lower. They have shot 10s of thousands of rounds all from a single lower receiver. It holds up to the abuse they have put it through.

I am still skeptical. After all, it is polymer. The polymer takedown pins, in particular, are short sighted in terms of functionality. Off-spec uppers can cause the polymer takedown pin to stick and trying to hinge open the upper receiver causes the entire front takedown pin to spin around. The trigger is actually rather decent but does not need to be made out of polymer. I still do not understand why someone would agree to using a polymer buffer tube and make it commercial spec. I have my suspicions that the buffer tube was chosen to be commercial spec since there would be more material to help support itself. I do have my doubts about the longevity of these components and will continue to be wary about the materials used in the lower receiver.