Matrix Arms 5.56 Foxtrot 15 Inch Keymod - $59.99

Here's my take on these Matrix rails:

First, in looking at several SG ads, it appears at least a handful of vendors are using these for their in-house builds; these include Karri's Guns, Geaux Armory, Alpha Shooting Sports, Center Mass Tactical, Mid-state Firearms, and a few others (including Wise). I can't speak to those, but perhaps others who may have purchased one of those can speak to their experience. I can only speak to using the Matrix rails in my own 'build from parts' uppers.

The barrel nut on these are smooth, with no indexing required. They need an odd-sized 1-3/16 crowsfoot, or you can clamp the barrel nut in the vise and use a tool like a reaction rod, or brownell's extension tool to torque from the other side.

While no indexing might seem like a benefit, keep in mind that this rail has no anti-rotation mechanism. The only thing that keeps them from rotating is clamping force from the three bolts clamping it to the (very smooth) barrel nut.

That said, I initially wanted to try one out for the various 'loaner' carbines that I take to the range for guests, friends, or random "you look interested, here try out a Modern Sporting Rifle" people that I've met at the range...hey each convert works in our favor, right?

Put together with Vibra-tite (VC-3) liberally applied to the barrel nut, and each clamping bolt torqued to 27# I cannot turn the rail on the barrel nut by hand. I have no doubt that enough force would turn it (or the barrel nut itself), but I've had the first loaner upper I build with one of these Marix rails at the range many many times and not had an issue with the rail turning even a hair. Which is good, since unlike the Midwest Industries rails, which have steel inserts for the bolt to screw into, the bolts on these Matrix rails screw directly into the aluminum of the rail. 25-27# is about as high as I'd want to torque the bolt in at. YMMV, at your own risk for higher torque.

Since that time I've built a handful of other loaner uppers using various Matrix rails (Charlie mostly, and a few Foxtrots, no Victors) and not had issues with any of those loaners in any of the builds done (9mm, 300blk, and a few other 5.56 in different BBL lengths). Neither have I had any issues with the rail bending, distorting, etc. or issues with the zero changing due to issues with the barrel nut. There is a review out there, somewhere, that I saw where the guys did manage to bend one up with quite a bit of abuse.

Would I recommend this for for 'That one gun'. No, while I think it works just fine for a range gun, loaners, maybe even a truck gun, I'm not confident enough in it to stake my life on it. To each his/her own there, I'll keep building with my MI/Samson/Seekins rails for that application. Though I would not hesitate to build more range loaners using these Matrix rails.

These are definitely above cheap ebay junk. I've had to deal with folks who've used cheap ebay junk and these at least seem to actually be 6061 and have in-spec Pic width and rail height.

I've purchase these from a few vendors and have had a few shipped with less-than-stellar anodizing. I am not sure if they are sold to the vendors 'in the white', then finished in-house, or they are shipped pre-anodized. Either way, the only issues I've had have been not-great anodizing, and those were sent back. NOTE: In relation to Wise Arms (to which this ad is attached) I have not experience that issue.

Hope that help folks in looking at these. They work, I've had no use issues, I have no issues recommending a range gun, but I'd save a bit more money if you are building 'that one gun'.