Last year, Midwest Industries (MI) released a highly evolved, second generation update of their popular Gen 1 SS-Series tube rail.

Fight Club Custom has a version of the rail coming out soon – specifically for PTW – so I thought I’d refresh this review/install, which I originally published on the Systema PTW forum, in August 2012.

I really liked the look of the new rail but, more importantly, I was really attracted to the low weight and the narrowness of the outer diameter (OD). In fact, I liked it so much, I bought it the very first day it went on sale.


Specs and a full list of parts included can be found at MI’s website.

The rail’s finish and the quality of machining is outstanding. I’ve yet to see an RS rail that doesn’t exude quality, but this rail is just excellent – especially considering it’s at the cheaper end of the market and more comparable in cost to high end airsoft rails. The anodising is flat and resistant to wear, the markings are clean and there are no sharp edges – everything is contoured and well finished.

The Gen 2 SS-Series is more than just a refresh of the Gen 1. It’s a complete redesign. The biggest single revision is the way the rail attaches to the receiver. Gone is the old system, where the rail threads-on to a proprietary barrel nut and is secured by a contra-rotated lock nut and anti-rotation is provided by a single screw (similar to the method still used on Yankee Hill Machine rails).

The Gen 2 utilises a clamping system similar to that popularised by the Troy TRX, but it fits over a proprietary barrel nut, which incorporates anti-rotation lugs in abundance.

Not only this, but unlike Troy and other brands which use or have used the clamp system, clearance between the receiver and the clamp area of the rail is more than enough to shotgun the receiver all the way open. You can see the gap, here:

So, no modification is required.

The other elements in the Gen 2’s redesign, which I specifically see as highly evolved, are the low weight and the narrow OD. Tube rails are getting narrower and narrower. The Gen 1 had an OD of 2.00″, as did a lot of tube rails of that generation. The Gen 2 is the narrowest of the true tubes, at 1.50″ in OD. The Noveske NSR – which I also own – is 1.48″, but clearly that has an angular cross section. There’s not much in it, in any case. Compare that with the 1.74″ of the Troy Alpha and the 1.80″ of the Samson Evolution and you can probably tell that this isn’t the kind of tube that will easily recess a suppressor.

In terms of weight, including the proprietary barrel nut, the Gen 2 is the lightest tube out there. The Noveske NSR is lighter, per se, but it has a heavier barrel nut. Either way, again, there’s not much in it.

Anyway, the Gen 2 spoke to me and I decided I wanted it for my Supa Lite Carbine build.

The idea here was to keep the balance and handling of the classic carbine, but to simply replace the plastic handguard – which is oversized by today’s standards – with a modern, slim, tube rail.

I also wanted to retain the carbine’s iconic A2 front sight – which I think has a disproportionately positive effect on the look of the gun. So this is my take on classic with a twist, using the Gen 2 rail.

Installation pretty much follows that of the Troy Alpha – aside from the clamping system, which is a no-brainier. An imperial allen key is included for the bolts. The Gen 2’s packaging (a blister pack, no less) includes full instructions and the all important barrel nut torque specs.

Helpfully, the Gen 2 comes complete with a torque wrench head for the barrel nut. I’ve applied a little grease to the receiver’s threads and have hand tightened the barrel nut.

Don’t forget to place your hop/barrel assembly and cylinder in the upper, to support from the inside while clamped.

Here’s what’s required:

It’s very easy to time the nut to 12 O’clock, as the wrench head has a cut out, which allows you to get a good view. Here’s the barrel nut timed:

You can see that the barrel nut, which is supplied with the rail, is like the reverse of a standard barrel nut. The teeth are at the receiver end:

I used a carry handle to help align the rail, while tightening the rail’s clamp:

Almost there…

Et voila!

I had a mare getting the A2 sight on (it was a new outer barrel, sight and pins), so as you can see, there’s only one pin holding the sight on – although it’s perfectly secure.

First impression when I used it? This is not a comfort build. But wow – just wow! It’s so light, agile and clean 🙂