Home Reviews MWG 40 Round Polymer AR-15 Magazine Review

MWG 40 Round Polymer AR-15 Magazine Review


Rifle magazine maker MWG recently released their 40 round polymer magazine for the AR-15. Designed by firearms engineer Ivan Kolev (who also designed the Bulgarian high capacity AK magazines) the new MWG 40 round polymer magazine features an ergonomic waffle design, which I tend to prefer over the smooth design of traditional steel AR magazines. It weights in at just .4 lbs, which is comperable to many 30 rounders on the market, and is only slightly longer than a 30 round polymer magazine at just 9.25 inches long.

MWG 40 round magazine next to a Magpul 30 round PMag

What makes the MWG polymer mag different than many other polymer mags on the market is the steel reinforced feed lips, we tested this with a magnet just to be sure. You can see the steel reinforced lips  in the picture below. While a non-steel reinforced polymer magazine would probably work just as well, the added strenght to the feed lips help ensure durability and reliable feeding, something very important on the battlefield. The MWG 40 rounder is made in Bulgaria and works with both .223 and 5.56 ammunition.

MWG 40 round magazine feed lips
Steel reinforced feed lips

MWG tested their 40 round magazine in both full auto and semi M4, AR-15, M16A1 and M16A2 rifles. We tested the magazine in our 16″ AR-15 carbine budget build rifle (more on that in a later post). It fit our rifle’s magwell pretty much spot on, it wasn’t too tight or had to be forced to seat, and it had no play or wobble whatsoever. The magazine spring and follower were both smooth and stable with virtually no tilt or creep. The magazine base plate is removable with the push of a button for easy maintainence. I usually take my magazines apart every fourth or fifth range trip to clean and inspect them, the MWG magazine was easy enough to take apart and reassemble.

We tested the MWG 40 round magazine over 4 range trips and put around 500 rounds through it (in both our budget build AR-15 as well as a friends Bushmaster AR-15) with zero failures to speak of. We used new factory brass .223 and 5.56, reloads, as well as various Russian steel cased loads. The MWG 40 round magazine ran like a top and absolutly refused to quit. The only downfall to the extended 40 rounder is when firing prone, which isn’t a negative to just the MWG 40 round magazine in particular, but to extended magazines in general.

The MWG 40 round mag with our M4 budget build

If 30 rounds just isn’t enough, the MWG 40 round polymer magazine fits the bill nicely. It has since become one of my most used magazines and is always in my range bag when I head out to shoot my AR. At just $25.95, the MWG 40 round polymer magazine won’t break the bank either. Check them out at www.mwgco.com.

Capacity: 40 Rounds
Caliber: .223, 5.56mm
Weight: .4lbs
Dimensions: 9.25″ x 2.5″ x 1.875″
Manufactured in Bulgaria

Check out all of our past reviews at our Reviews Page.

Follow-up Review Oct. 2012

It’s been well over a year since I’ve been using the MWG 40 Round Magazine, we first reviewed this mag in June of 2011. Over the course of that time I’ve probably fired a almost 800+ rounds through this magazine. So far so good still, no signs of cracks around the feed lips or anywhere on the magazine body. I have taken it apart to clean it a few times, I haven’t experienced any jams or miss feeds. Another plus? The price has actually gone down to just under $20.


  1. I have two, it’s worked well for me. I had some issues with Wolf .223 but it was nothing major. I would rather have a few of these then a drum mag any day.


Please enter your comment!
Please enter your name here