Parallax Tactical \ PXTreme FFSSR MLok Rail Review

[Marlin 795]

Hey guys,

Like many of you I really enjoy reading reviews of new products, especially ones that are not super commonplace or found in most gun stores. Recently I received one of the Parallax Tactical \ PXTreme FFSSR 15" MLok rails and figured I'd drop it on the only 16" gun I have--a nearly brand new Sig M400 that I got in a trade. I've been upgrading the gun as I've come across good deals, and finally had enough to put together most of the rifle and post up some photos.

Some background on me: I am an independent manufacturing consultant in for extreme sports (in the outdoor segment), primarily with a focus on soft goods and injected plastics. I do dabble with machined and extruded products, and have worked on projects supplying outdoor\shooting products to vendors like WalMart, Academy, Cabelas, and more. Lately I've been doing a bit more marketing and web development work, and set up an very amateur photo studio at my house which I enjoy using. I have been an avid shooter since 2008 (about when I graduated from university). While the photos are pretty amateur in nature, I think they are useful for people to see a closer look at the product as it would arrive to you.

Specs from Parallax (taken from the Keymod page, since the MLok ones do not seem to be posted):


15" OAL
6061 T6 Extrusion
Type III, Class 2 Hard Anodized and Bead Blasted Finish
9.9 oz Rail Weight
13.4 oz with Barrel Nut and Screws
Features our new barrel nut, 18% lighter than previous at 92g. (Noveske at 84g.)
10-32 holes on top rail to mount Sling Studs and future accessories.
Included anti-rotational QD hole
Includes Barrel Nut, Screws and Includes Optional Shims for spacing
Installation Instructions Included
Made in USA with Domestically Sourced Materials
1.52" OD
1.35" ID (Will not fit most suppressors and KX3.)


The rail came in a pretty generic cardboard box, with the instructions, barrel nut, hardware, and shims:

http://i.imgur.com/elF0hCt.jpg
http://i.imgur.com/GnoD1lU.jpg
http://i.imgur.com/CDm1hJF.jpg
http://i.imgur.com/eV60IWa.jpg

The inside cuts that comply with the MLok standard:
http://i.imgur.com/ZUyK9So.jpg

The victim. A bone stock Sig M400, the Parallax rail \ barrel nut, VLTOR MUR replacement upper, and the wrench I used for doing the work. Not pictured is the gas block I intended to use.

http://i.imgur.com/xEBa5z7.jpg

Made a few mistakes, most of which were due to the very-poor construction of the Wheeler AR Wrench. The barrel nut portion the wrench is seemingly sized incorrectly, which led to snapping off a few teeth from the barrel nut. While I neglected to get any photos of the wrench (the barrel nut side), you can see from the castle nut wrench that the nubs are quite rounded and sized incorrectly. I then replaced it with a Tapco AR tool (the new made in USA green one) and have been thrilled with it.

http://i.imgur.com/sZXUYuy.jpg
http://i.imgur.com/UTr5G5B.jpg

Got the FSB removed by angling the FSB in a vice, and then closing the vice to push out the pins. I read about this on the Vuurwapen blog and it worked SO much better than beating on it with punches.
http://i.imgur.com/35vczV7.jpg

I had planned to use the extra BCM gasblock I had, but I realized my LGS had it marked as a .750 and it was actually for a .625 barrel--so I rush ordered a replacement off Amazon that was allegedly made by Troy. Of course I had discovered this after I'd already put the pin through the gas block, so here's a pic of the BCM that was excited to use.

http://i.imgur.com/QvG0Gul.jpg

Troy gas block arrived the next day, and they were kind enough to not include a roll pin. So, I had to grab one from my tech box and then compromise with a slightly longer pin.

http://i.imgur.com/x2NrfER.jpg
http://i.imgur.com/xdfAFTE.jpg

Got it all mounted. I was sad I had to replace a BCM product with a Troy, but I wanted to get the gun up and built.

http://i.imgur.com/R7aH7Ie.jpg

I torqued the barrel nut in place. I must admit that the shims \ timing of the barrel nut to get the screw holes was tedious, but I got it to work:

http://i.imgur.com/pdPBV9r.jpg
http://i.imgur.com/gQjpOJd.jpg

Fully mounted up after torquing the side bolts to 50in\lbs and the bottom to 30 in\lbs:
http://i.imgur.com/zHKXpXy.jpg

I am waiting on a Burris XTR II 2-10, Geissele trigger, and my suppressor to show up. If you look carefully you can see that my A2 Flashider is canted, as I am simply using it as a thread protector until I get my Specwar brake in. Then I will update the thread with a complete build.

I am happy with the product and would recommend it to others looking for a lightweight MLok rail at a good pricepoint. The anodizing is uniform and the part was free of burrs, defects or inadequacies (more than I can say for the MI rails that I've owned).

Pros:

Inexpensive compared to similar options ($180ish)
Very lightweight
One of the first fully-compliant MLok rails to the market (sorry ALG)
Adequate packaging, instructions etc


Cons:

Not from a comparatively "cool" brand
Did not include a crow's foot torque wrench attachment


If anyone from Parallax is reading this, I my two suggestions would be to include the correct crow's foot wrench needed and to host your instructions on your website. I went through 2-3 crow's feet before finally just emailing you for a brand recommendation for a wrench of the correct head width (the thickness of the actual wrench head) that would fit on the flats of the barrel nut. I am sure that you could find a tool wholesaler that would sell an inexpensive wrench head in bulk for a few dollars like I did on eBay. I very pleased otherwise, and look forward to grabbing some of the new Arisaka products for my MLok rail.

[dmd08]

Sig 516 is a piston gun.......

[.46caliber]

Thanks for the write up very detailed and the photos are good.

One thing worth clearing up. The rifle is not a SIG 516. SIG 516/716 are piston gas systems not DI as the rifle shown. I don't think that the PXT would fit over the piston systems.

How did you support barrel/upper when removing the barrel nut?


Sent from my Nexus 4 using Tapatalk

[Marlin 795]

Sig 516 is a piston gun.......

Woops. I also have a Sig716 and got the model number confused. Corrected.

Thanks for the write up very detailed and the photos are good.

One thing worth clearing up. The rifle is not a SIG 516. SIG 516/716 are piston gas systems not DI as the rifle shown. I don't think that the PXT would fit over the piston systems.

How did you support barrel/upper when removing the barrel nut?


Sent from my Nexus 4 using Tapatalk
Thanks.

As noted above I have the 716 and I confused them.

I snagged one of the Geissele reaction rod copies from Botach for $35 and used that. It is one of my favorite tools in my box next to my new Arisaka scope leveler and FAT wrench. All of them put a smile on my face when I use them.

[Iraqgunz]

Did you dimple the barrel for that low profile gas block before you installed it?

[Marlin 795]

Did you dimple the barrel for that low profile gas block before you installed it?

I had initially planned to with the BCM block, but as noted above I had to actually go with a Troy clamping block because the BCM one I purchased was the wrong ID.

I just liked the way the BCM block looked in the photos, but didn't end up using it.

PS: Would love to attend one of your armorer's courses, and I'm in Phoenix. Any idea when the next one is?

[Iraqgunz]

I am confused. You used a clamp on styled Troy block? Also, in your pic, it appears that you mounted the block fully to the rear of the journal. Is that the case?

There will most likely be one in spring at SGC.


I had initially planned to with the BCM block, but as noted above I had to actually go with a Troy clamping block because the BCM one I purchased was the wrong ID.

I just liked the way the BCM block looked in the photos, but didn't end up using it.

PS: Would love to attend one of your armorer's courses, and I'm in Phoenix. Any idea when the next one is?

[Marlin 795]

I am confused. You used a clamp on styled Troy block?.

Yes, my local gun store sold me a BCM block that was for a lightweight barrel, and I needed the larger profile. As seen above in my post. Quoted below:


I had planned to use the extra BCM gasblock I had, but I realized my LGS had it marked as a .750 and it was actually for a .625 barrel--so I rush ordered a replacement off Amazon that was allegedly made by Troy. Of course I had discovered this after I'd already put the pin through the gas block, so here's a pic of the BCM that was excited to use.

SNIP

Troy gas block arrived the next day, and they were kind enough to not include a roll pin. So, I had to grab one from my tech box and then compromise with a slightly longer pin.

SNIP
SNIP

Got it all mounted. I was sad I had to replace a BCM product with a Troy, but I wanted to get the gun up and built.


Also, in your pic, it appears that you mounted the block fully to the rear of the journal. Is that the case?

No, it is not against the boss\journal, but I should add a picture showing that.

[JChops]

*One of the first fully-compliant MLok rails to the market (sorry ALG)

The ALG rails are fully-M-LOK compliant. Not to mention 10 times nicer than that piece of shit rail.

[Marlin 795]

The ALG rails are fully-M-LOK compliant. Not to mention 10 times nicer than that piece of shit rail.

Their first ones weren't, lacking the inside cut that the T-Nut braces against. Their later release included this cut.

And thanks for the pleasant remarks.

[.46caliber]

As noted above I have the 716 and I confused them.

I snagged one of the Geissele reaction rod copies from Botach for $35 and used that. It is one of my favorite tools in my box next to my new Arisaka scope leveler and FAT wrench. All of them put a smile on my face when I use them.

OK, I'm just trying to figure out why the trouble with the barrel nut and wondered if how you had the vise setup had anything to do with it. I just used the Wheeler wrench and a ReactionRod to remove the GI nut on my SIG M400 and had no trouble at all. Did you use your support hand to hold the wrench face tight against the nut to make sure the pins didn't slip out of the nut as you applied force?

Also, the picture of the gas block and tube installed isn't a clamp-on block. It's a set screw block. I think that's why Iraqgunz was asking. If the link below is the block used, the barrel should be dimpled so the set screws can bite in and properly hold the block in place.
https://troyind.com/products/gas-block-750-1

I picked up my ReactionRod in one of Geissele's tool kits, and likewise, they are a dream to use. His gas tube roll pin starter is a pretty slick little tool.

[.46caliber]

Their first ones weren't, lacking the inside cut that the T-Nut braces against. Their later release included this cut.


The compatibility issue with the T-Nut version was the outside of the tube, I had one. It had the radius of the tube on the surface where the M-LOK slots were cut. The updated version has flats machined along the M-LOK slots on the outside so that attachments secure to a flat and not radiused surface.

[Merle]

The ALG rails are fully-M-LOK compliant. Not to mention 10 times nicer than that piece of shit rail.

Classy! Do you have some experience with this brand or just talking shit? The ALG rail is about as ugly as they get.