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Matrix M4 GBB AR-15 Gas Blowback Airsoft Rifle w/ Reinforced WA System by S&T (Model: M4A1)

ID: 75714 (GR-MTX-ST-GBB-05-BK)
4.7 stars, based on 21 reviews
Matrix M4 GBB AR-15 Gas Blowback Airsoft Rifle w/ Reinforced WA System by S&T (Model: M4A1)
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  • Utilizes the Western Arms gas blowback system ensuring reliable performance with a plethora of aftermarket parts and accessories
  • Injection molded polymer receiver provides rugged durability without the additional weight of a metal receiver
  • Improved gas efficiency, reliable feeding and firing in full auto
  • Adjustable LE type stock
  • Removable carry handle with 20mm accessory rail underneath, ideal for mounting optics
  • Injection molded polymer A1 style handguard

FPS Range: 340-380

Color: Black

Length: 765mm-855mm, Adjustable
Weight: 3300g
Inner Barrel: ~363mm
Magazine Capacity: 50rds Uses Matrix, G&P, Western Arms, King Arms, Inokatsu, and compatible magazines.
Muzzle Velocity: 340~380 FPS (Measured with 0.20g BBs and Green Gas)
Thread Direction: 14mm Negative
Gas Type: Green Gas
Fire Modes: Semi/Full-Auto, Safety
Package Includes: Gun, Magazine, Vertical Foregrip
Hopup: Yes, Adjustable

Manufacturer: Matrix. (USA) S&T (Asia)

About Matrix

Established in 2001 for Airsofters by Airsofters. Team Matrix thrive on the vision to better the sport of Airsoft with affordable high quality Airsoft equipment. With decades of experiences as Airsoft enthusiasts ourselves, we live, sleep, and breathe Airsoft. Matrix offers a wide selection of skirmish grade replicas from rifles to pistols, a wide variety of accessories, and tactical equipment from helmets to boots. It is the Matrix mission to prepare every Airsoft shooter the perfect experience!

About S&T

S&T is a group of Airsoft enthusiasts that produces rifles and parts based on the trends in the Airsoft industry. Their mission is to supply a wide range of quality products with the most competitive pricing for dealers and consumers alike. S&T was founded in 2009 with their HQ office located in Hong Kong, a subsidiary office in Japan, as well as Airsoft / Airgun manufacturing facilities in China.

21 Customer Reviews

(Write a review)

by Marben F. on 05/28/2020
"I bought the keymod 7" version.

This is my first GBBR, and it has exceeded my expectations especially for the price.

This is a great, affordable way to use this as a training platform and milsim. Polymer build makes it light. I feel like if I'm too rough with it, it might bend and break. So I take some care when handling it.

Magazines are cheap. Whenever I try to fill these with propane using an adapter, they leak from the side of the valve. I tried three different propane adapters including the Matrix polymer one from here, but they all seem to leak. Tried filling my GBB pistols and they don't leak like these mags.

Otherwise, they have pretty decent gas efficiency when shooting. I can probably empty 1 and half mags before they start sputtering. I usually only fill about 40 rounds as the spring starts to get tough around that count. Full auto has great ROF (can't tell you a number), but it's satisfying enough.

As for loading the mags, you need a speed loader with the GBB adapter (that little clip of plastic that comes with your standard pistol magazine sized loaders). I've recently learned this and luckily had one stashed away. Otherwise, you will need to load each BB one by one by hand. I tried using the old reliable speed loader sold here but that doesn't work. I wish they had that in the "You may need this" section of the listing.

Magazine stock screw I noticed would fall out sometimes after full auto. Keep that in mind when playing on the field. I would recommend either securing it somehow or buying a better stock that can handle the recoil. Maybe it's just mine, but something to note.

If you're looking to use a sling with these, buy QD sling mounts. There are no options to use traditional slings out of the box. I personally use a QD keymod sling mount for the front and just a zip tie around the stock hole and it works fine.

Overall, for the price, this is a solid first GBBR and should give you an idea whether or not you want to invest in more higher end GBBRs or not. I personally will continue to purse GBBRs as I like to use them more for training then skirmishes.
by Chris K. on 02/16/2020

This thing is practically indestructable!

I own a shooting simulator, we have this firearm tethered and use it at a minimum 1,000 rounds DAILY.

The only issue we have had after two months of use, was the charging handle breaking, and the hammer spring being too weak and breaking. Easy to fix issues. Otherwise this thing is unstopable!

I ended up buying four more and running them on all three lanes.
by John K. on 11/13/2019
"Bought the 9 inch Keymod version. It shoots good and is accurate up to 170 ft and hit a half man target over 50 yards. I’m going to keep it brief.

Hard kicking
WA parts compatible
Good gas efficiency
Plastic receivers appear to be a strong poly not like old abs plastic guns.

Mag price
Sights are hooky

People make comment of weird springy sound, which is just the buffer spring making noise - normal and is audible in real AR type riffles. Plastic receivers can be more durable than zinc alloy metal receivers. Buy with confidence - I just spent an additional 160 dollars on steel internal parts, and a new steel bolt and it is more solid than any other GBB out of the box for less money than a GHK

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