SureFire Institute has just introduced their new Polymer lower receiver for AR-style rifles.
Developed in conjunction with E3 Arms, they took a look at the internal firing mechanism to improve trigger pull and reset. However, the selector lever can be moved to Safe with the hammer forward or to the rear. The SFI-15 can be stored on Safe no matter what condition the rifle is in, and the weapon can immediately be placed on Safe while dealing with a malfunction.
It weighs 1.1 lbs. I realize many are hesitant to use a polymer lower but SFI says that the material has a tensile strength of 33,500 psi, tensile elongation of 2.5-3.5% and flexural strength of 50,000 psi.
Tags: SureFire Institute
If anybody can pull off a polymer lower it’s SureFire.
I don’t think Surefire itself is involved. I am pretty sure the Surefire Institute is separate from Surefire itself.
Rog…thanks for the info.
I’m not trying to start a fight. But what would cause you to think Surefire is the company that can build a polymer lower. Seems to me there are several companies (MAGPUL maybe) that have much more experience with polymers who could pull of this feet perhaps better.
The plastic isn’t the problem. There is a simple fix to these but no company wants to do it.
I get why there are plastic 80% receivers but I don’t get the why behind complete plastic receivers. Is it a weight thing? One pound difference isn’t significant enough when durability is questionable.
If it was significantly cheaper than an aluminum I would grab one for a .22 build but I’m guessing it won’t be.
This. But hey, at least they incorporated the iconic POF-style “melted” trigger guard, and literally no other aesthetic styling that you get for free when injection molding a part. This is definitely a “WTF?” product in my mind.
RFfromNOVA,
Good point…Magpul and any of the reputable polymer pistol manufacturers could probably be successful. I hold SureFire in high esteem so that is why I commented. Personally, I probably would not buy a polymer lower unless it was clearly demonstrated to be very durable.
33k is about 75% strength of 6061 and about 50% the yield tensile of 7075 aluminum.
Now… Is this probably fine. Yea. Probably. It concerns me that the receiver extension tail is the same size and shape.
Would I ever personally buy a polymer lower that was in the exact same shape as it’s aluminum counterpart – F-NO.
Yup. The weak points are an easy fix if they wanted to do it but no company does. I would grab one for a dedicated .22 build IF it was significantly cheaper than an aluminum receiver. I don’t think it will be.
It comes down to why? A 1 pound weight savings isn’t worth the questionable durability. I want these to succeed but with out the required mods I feel it won’t.
FYSA, Surefire Institute is not the same thing as Surefire. The training division was spun off and is now an independent entity run by some retired cops from Huntington Beach, CA. There is still a connection, but I would not consider this a Surefire product.
So my understanding is this lower will have dedicated fire control components that do not swap out – “they took a look at the internal firing mechanism to improve trigger pull and reset.”
That seems to remove a lot of after market support to that #1 or 2 thing that you can do to enhance a basic AR. I am struggling with the marketability of this item, beyond the limited super lightweight crowd.
So its not as strong as aluminum and because it has “Surefire” on it it will probably still cost more than a good quality forged 7075 lower. Brilliant…
I am buying a good friends son, who is graduating from our local police academy, an AR15. On that list from the police requirements for said AR is it MUST be a metal receiver.
When I question officers on this they do not have any real solid answer for why this is but the 2 reasons that come up as the most reasonable are issues with heat, both from firing and just the darn South Texas hellish heat and being in their squad car and solvents getting on it.
They reason, better safe than sorry.
Before y’all go bashing polymer lowers, check out Tennessee Arms Company. They use brass inserts in the receiver extension hole as well as the grip screw hole.
There are tons of abuse videos online of the magazine well being crushed to the point it touches in a vise, then a mag is inserted and drops free.
Oh, and Frank Proctor personally told me he has at least one and beats the snot out of it. He loves it.
Weight adds up over time. There is a decently large lightweight movement where people are spending 3k on an AR(not including optic) to get it under 4.5 pounds. There are even some under 4 and lighter. I personally feel that any item that pushes technology forward and innovates is good for the industry.