The Matador Arms’ New Montgo-9 Upper Receiver

Matador Arms has announced the Montgo-9: it’s a monolithic blowback-operated billet 9mm upper receiver that doesn’t require a buffer to cycle. Not an AR15 style buffer (and the corresponding buffer tube) anyway. 

Think back to 1963 (the AR-18, not Avengers #1) and you’ll kinda get the idea.

BEORE. The Montgo-9: a monolithic 9mm blowback-operated upper receiver, with no buffer. Compatible with AR-15 and/or AR-9 lowers. Utilize the Matador Arms Sidewinder to make yourself an AR folder.  – Photo credit to @Matador_Arms
AFTER. Just look at this thing. It oozes “tacti-cool” vibes. You know it, or at least I know it, and I love it. It is okay if you feel the same way. We get it. It certainly makes us want to throw on some unnecessarily tacticalized tactical pants, flannel shirts, and black gloves with knuckle-covers to go run high speed, low drag drills. Or just hit the range in general, honestly.

Matador Arms Montgo-9 AR9/PCC Upper Receiver

Compatible with any AR-15* and/or AR-9 lower, the Montgo-9 gives shooters what Matador Arms calls “…endless build possibilities”, all while being compact and versatile. 

We’ve got the upper receiver separated from both sides so that you can get a good look at it.

You want some specifications? We got your specifications.

  • Solid end receiver…does not require a buffer
  • Hard anodized billet aluminum
  • 5.5″ barrel, 4140 Nitrided 
  • ½x28″ threaded barrel
  • Full-length integral Picatinny rail for installing optics or sights
  • 3.5″ bottom Picatinny accessory rail 
  • Non-reciprocating charging handle…can be used on right or left side
  • 4140 steel nitrided bolt & trunnion for durability
  • No tools are required for field stripping
  • OAL: 12.125”, Width: 1.47”, Weight: 3.5lbs
  • Note: AR15 lowers will require a MagX adapter or something similar to accept 9mm pistol magazines. 
The Montgo-9 may be legit tactical or tacticool depending on your actual needs, but one thing you can’t dispute is how good that trigger discipline looks. 


As Matador proclaims in their social media posts, “The Montgo-9: It’s a 9mm blowback-operated upper receiver, with no buffer! Compatible with AR-15 and/or AR-9 lowers.” – Photo credit to @Matador_Arms

The current version of the Montgo-9 is the “K” version, featuring a 5.5″ barrel threaded to 1/2×28″. The back cap shows that no buffer is required, allowing for many compact options. In addition, the non-reciprocating charging handle is reversible. The Montgo-9 has a total length integral Picatinny rail on top and a 3.5″ bottom accessory rail. 

Here are some more setups and mock-ups of the Montgo-9 for your viewing pleasure.

The Montgo-9 upper receiver is made of aluminum, and the bolt and trunnion are 4140 steel for durability. Weight is 3.5lbs with an OAL of 12.125″ and a 1.47″ width. 

The Montgo-9 catching some range time with a Sig Sauer ROMEO5 mounted on top.

MSRP of the Montgo-9 is $549.99. Shipping of the Montgo-9 is projected for Q4 of this year. 

Options from Matador for the Montgo-9

The Matador MagX Adapter

The Montgo-9 adds to Matador’s 9mm product offering. Matador recently announced their AR-9 80% billet lower receivers, the first run of which is shipping mid-September. Matador already manufactures the Mag-X, a mag block adapter enabling the use of P320, Glock, M&P, and CZ-75 pistol mags in their AR-15 lowers. 

Here is some of the info from Matador’s website about the Mag-X:

The Mag-X is available for G17/G19, P320, CZ 75, M&P, and CZ P-09 & P-10 mags. In addition, the Mag-X allows you to use your pistol magazines in any AR-15 mil-spec lower.

The Mag-X fits any standard AR-15 lower receiver; no modifications are required to your lower or magazine; it installs in seconds, and there is a built-in magazine release. It also locks into place with the standard AR-15 catch. The Mag-X also features a steel ejector and magazine catch.

However, it is only compatible with mil-spec AR-15 lower receivers, combined with a 9mm upper with a Glock-cut bolt. It also has no last-round bolt hold open.

The Matador Sidewinder

Matador’s Sidewinder is a folding buffer tube adapter that will fold up anything with AR buffer tubes threads WITHOUT a moving buffer inside. And, the adjustable Regulator muzzle brake comes in 9mm, which could top off the Montgo-9 perfectly. 

According to Matador Arms’ website, “This AR buffer tube folder allows you to go compact ultra-solid lockup. It’s [the Sidewinder] lightweight, strong and reversible so that you can fold in either direction and know it’ll stay put.”

Here is the sidewinder buffer tube folder in action with the Montgo-9.

The Matador Regulator Muzzle Device

You might have noticed the Montgo-9 is shown in some of the pictures with and without a muzzle device. The muzzle device demonstrated in some of the photos is the Matador Arms’ “Regulator” that they offer separately.

According to Matador Arms’ website, it is “the first of its kind, adjustable port, muzzle brake!  Take a look at the most versatile and adaptive brake on the market! The Regulator allows shooters to effectively manage muzzle blast and recoil, without any tools or downtime.”

Here are some of the specifications on the Muzzle Device as well:

  • Allows the shooter to manage muzzle blast and recoil reduction to suit their needs
  • 60+ engaged settings from complete shutoff (0%) to fully open (100%)
  • No tools for adjustment; adjust by clicking the locknut
  • Triple chamber, high-efficiency muzzle brake
  • When open, vertical ports reduce muzzle climb
  • High-speed follow-up shots
  • When closed, gas is forced forward, away from the shooter
  • 4140 steel, durable nitride coating
  • 3.6″ LOA
  • 1.08″ OD
  • 6.8 oz.

With all three of these options and the Montgo-9, this seems to be a pretty solid and modular combination the makes up *almost* an entire weapon system. But only time will tell; we are certainly For the release of the Montgo-9, Quarter 4 can’t come soon enough.

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