Review: Midwest Industries One Piece FF Gen -2 SS-Series Rail

The Midwest Industries One Piece FF Gen -2 SS-Series Rail (MI Gen-2 SS Rail) is part of the current crop of slim, lightweight, slick-sided free float rails. Many of these free float rails are so similar that, at first glance, it can be difficult to differentiate one from the other. That appears to be the case with the MI Gen-2 SS Rail until you take a look at its specification. Two specs in particular make your eyes pop out of your head – 9.3 ounces and 1.5 inches – the weight and the width. Does that have your attention? It certainly captured mine.

The MI Gen-2 SS Rail is available in several lengths (7”, 9”, 10”, 12”, and 15”). This review will deal with the 12” version though the features are identical across the entire line.

MI SS Series Gen-2 Free Float Rail


The MI Gen-2 SS Rail is a slim, lightweight, slick-sided free float tube. It features a continuous top rail across its entire length and the ability to attach accessories like rails or hand guard covers in multiple locations along its circumference. This design strategy reduces weight by allowing the end user to determine where rails are necessary. It also reduces the circumference of the rail allowing the end user to grip it more aggressively. It comes with 3 2.5” accessory rails (1 includes a QD sling swivel socket).

Midwest Industries was particularly successful with this strategy since they have reduced the weight of the rail to just 9.3 ounces (including the barrel nut) and the outside diameter to just 1.5” (excluding the top rail). That makes it one of the lightest free float tubes on the market and the slimmest one that I am aware that has an integral top rail.

The MI Gen-2 SS Rail are made from 6061 aluminum and hard anodized for durability. They utilize a proprietary barrel nut to mount the tube to the upper receiver. The tube attaches to the barrel nut with a friction fit via 2 large hex screws. The barrel nut is checkered to enhance this friction fit.

MI SS Series Gen-2 Free Float Rail Barrel Nut MI SS Series Gen-2 Free Float Rail Attachment

Observations from Use

You have probably gathered by now that the MI Gen-2 SS Rail is very lightweight and very slim. Until you try one of these rails, those are really just numbers on a screen. The lightweight and slim design actually translates to functionality in use. For instance, I typically like to use a vertical grip on a traditional 4 rail free float tube. However, with the MI Gen-2 SS Rail, I don’t need one because I can wrap my hand around the rail and pull the carbine back into my shoulder aggressively to control recoil. That saves additional weight. The rail is so slim that I can wrap my hand around it and touch my thumb and index finger (or any other finger).

It is easy to put the weight of the MI Gen-2 SS Rail in perspective. It weighs just 9.3 ounces including the barrel nut (before adding any accessory rails). That is the exact same weight as a standard polymer M4 hand guard with double heat shields. So, for the same 9.3 ounces, you can have a cramped polymer hand guard with no light or sling mounting options or a 12” extended rail. The MI Gen-2 SS Rail delivers a lot of functionality per ounce.

MI SS Series Gen-2 Free Float Rail with Covers

There are a host of accessories already available for these rails. Midwest Industries supports them with direct connect handstops, additional rail sections, and hand guard panels. I find the hand guard panels with an integrated handstop to be a great value. Impact Weapons Components also makes several items in their MOUNT-N-SLOT line that work (use discount code “triggerjerk” for a discount at IWC). The 1.75” diameter mounts seem to work fine despite the slight difference in diameter. There are so many accessories available for these that you can attach everything you need without having to use an accessory rail which saves even more weight.

MI SS Series Gen-2 Free Float Rail with Handstop MI SS Series Gen-2 Free Float Rail with Accessories

I have 2 of these MI Gen-2 SS Rails and they have held up very well to use. The hard anodizing seems to hold up well. It often looks scratched but usually the “scratch” is just a scuff that wipes off easily. I have been able to put some honest to goodness scratches on them but that will happen when you are doing things like shooting on barricades and, you know, actually using your gear. The attachment system has been durable enough that, so far, I have had no issues with loosening, wobble, breakage, and anything else that you might be worried about.

Rails like these have a lot of application for the civilian gun owner (or anyone else). Their small diameter and light weight make them perfect for all you guys who like to build carbines “for your wife.” While the fairer sex often prefers lighter weight carbines, you should, too. That is especially true when rails like the MI Gen-2 SS Rail reduce weight while still maintaining (or even adding) functionality and great durability. Why wouldn’t you want a lighter gun if it was just as functional as a heavier one? The ladies (and delicate handed bloggers) will also appreciate that Midwest Industries does a good job of breaking the edges on the MI Gen-2 SS Rails so they don’t have the cheese grater feel that many similar products have.

MI SS Series Gen-2 Free Float Rail Muzzle End

Wrap Up

I really like these rails. Not only are they lightweight, slim, and durable, they are also a good value. None of the MI Gen-2 SS Rail models cost more than $190 and in most cases they cost much less than that. If you are going to drop the coin for a free float rail, you would be hard pressed to find a better value than these.

Check out the 12” Gen-2 SS Rails and 15” Gen-2 SS Rails at

6 Responses to Review: Midwest Industries One Piece FF Gen -2 SS-Series Rail

  1. Micah May 21, 2013 at 19:50 #

    Thanks for the review. I was leaning towards this handguard for my first AR build.

  2. Rugrash May 21, 2013 at 21:50 #

    Got one of the 15″ models on a 300 Blackout. Nice to know that the IWC hand stop’s screw actually is compatible (didn’t know that and I actually sell those products). This is one of the slimmest and lightest rails on the market and is nice if you want something a little different. The Seekins MCSR V2 is even lighter.

  3. Shawn May 22, 2013 at 10:58 #

    I put the 7″ Carbine one on my AR pistol build and I REALLY like how slim it is. It actually matches my upper receiver diameter perfectly.

  4. Molon Labe May 22, 2013 at 11:39 #

    I have the 15″ on a self built Midlength CHF 16″ PSA/S&W/ Tactical Machining/ Frankengun and I love it! Only downside is the mounting system. I would prefer if the locking screws actually bit into a bit of the Barrel nut like the new Geisselle rail.

  5. JeffZ October 9, 2013 at 23:42 #

    Looks nice, is lightweight and affordable but that mounting system does not look durable. Sure… a few range visits and maybe a couple of months down the line it might be okay but give it a while I just don’t think it would hold up. There’s also the issue of heat transfer being so skinny

    There is other lightweight rails in the Gen 2 price range (Troy, Rainier, Seekins) with similar specs as well that are probably better choices money and durability wise. Or you could spend $50-$70 more and get a Noveske NSR.
    Which is just as light as the Gen 2 with a much more durable mounting system and a more reputable company

    As the saying goes: Buy once cry once

    • Matt October 10, 2013 at 07:31 #

      Jeff, heat transfer is going to be an issue with all of these rails. The Gen2 SS rails are not fragile and they hold up fine. BCM even uses them on in house builds with their own branding on them.

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