Review: Suarez Tier One M4 PDW Upper

    We have an excellent contact at TSD Combat/Suarez group who really does a great job of sending us products to test and review. To me it really speaks well of a company when they are so eager and willing to show you that their products are well made, and the ease of communication usually means they also have good customer service. When I was notified I would be testing a pistol upper built to be accurate from the ground up, I got pretty excited. Last time I reviewed an AR15, the readers said that my 200 round test to determine reliability was not enough. Us writers do in fact pay for our own ammo, so it hurts our wallets to fire much more. Regardless, I feel that I owed the good people at TSD a serious test of their new upper… so I built a full auto lower using my 07/02 to test their upper:


    With their upper, the gun looked really awesome too:



    The specs on the upper:

    Aluminum Mil-Spec Heavy Phosphate Upper Receiver

    Mil-Spec Bolt Carrier Group:

    •     M16-cut carrier
    •     Machined from 8620 steel
    •     Mil-Spec phosphate coating
    •     Shot peened
    •     Properly staked gas key
    •     Chrome lined gas key and firing pin channel
    •     Bolt is machined from Carpenter 158 tool steel
    •     Shot peened
    •     HPT/MPI and marked
    •     Black o-ring insert on extractor
    •     High quality BCG

    9.2″ Keymod Rail Handguard

    •     NEW 9″ Suarez International KeyMod Handguard
    •     9.2″ OAL
    •     6061 T6 Extrusion
    •     Type III, Class 2 Hard Anodized and Bead Blasted Finish
    •     Same slot spacing to take any Magpul MOE rail accessory on the 45 degree slots.
    •     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
    •     1.52″ OD
    •     1.35″ ID (If adding a suppressor, check for fit)

    10.5″ Stainless Steel White Oak Armament Match Grade Barrel

    “If you examine the line at Camp Perry, you will see a virtual catalog of the barrel offerings from White Oak.  Some may question the “need” for a Match Grade barrel of this quality on a PDW, we do not.  These were originally made for a Special Operations Unit wanting MOA Capability out to 300 meters from the short barrel with Match Ammunition.  That is what you will get from these barrels.  You can certainly go cheaper elsewhere, but you will not find better quality or greater accuracy anywhere.”

    Stainless Steel Match Grade Barrel (With Full Match QC)

    •     Length: 10.5″
    •     Twist: 1:7
    •     Thread Pitch: 1/2 X 28
    •     .750 Gas Block Seat
    •     5.56×45 NATO Chamber
    •     Carbine Gas System
    •     M4 Feed Ramps
    •     Bead Blasted Finish

    Low Profile Gas Block
    All Mil-Spec Internal Upper Receiver Parts

    Read more by clicking here.

    So I headed to the range with 400 rounds of 55 grain PPU ammo (ten loaded mags plus some loose rounds). As the upper was built to be accurate, I got the accuracy test out of the way immediately before I got to test reliability (which is code for gratuitous mag dumps).

    Using Fiocchi 77gr. MatchKing ammo, I was able to put rounds where I wanted. I shot five groups of five rounds. Here is the best:


    And worst:


    I averaged 1.31 inches at about 70 yards. For a 10″ barrel, I thought the gun performed acceptably. Bear in mind that I am an average rifleman at best.

    After that my friend and I plinked at some steel with 55 grain stuff and got our fill of tagging the ringers down range:



    After that, it was time to hit the fun switch:



    The upper ran perfectly, as expected.

    So to really put this thing to the test I brought out 10 loaded 30 round magazines, gloves, and set my phone on a little tripod to record the mayhem. Unfortunately my friend did not know I hit record, and he himself pressed it again and turned it off. However, all was not lost, he did manage to catch some of the action on his camera phone:

    I have never performed that many mag dumps back to back to back, and it was crazy. The gun got hot as could be, the gas tube was glowing, and the cyclic rate began to increase!

    300 rounds fired in this fashion is, I think, a pretty intense test considering that a load out usually consists of only 6 mags or so. The gun did experience one stoppage, but it was not the gun’s fault: there was a genuine dud where a full primer strike occurred but it failed to ignite. That said, other than this failure, the gun successfully turned the magazines into noise!


    So a quick rundown:

    The Good:

    • Accurate
    • Slim
    • Light
    • Reliable
    • Great sights
    • Full auto ready
    • Keymod rather than rails
    • Uses One Source’s new Valmet style hider/wire cutter

    The Bad:

    • The upper is not cheap, coming in at $859.99
    • Need a pistol or NFA lower to run this upper
    • Some people may not like keymod, and instead prefer picatinny rails

    So for me personally, this upper does a great job for anything I would use it for. It has accuracy and reliability going for it, and these are the most important factors I looks for when buying a firearm.

    To learn more about the upper, visit One Source Tactical and give it a look. Also feel free to email me with any questions and I will be more than happy to help you as best I can!

    Alex C.

    Alex is a Senior Writer for The Firearm Blog and Director of TFBTV.