Magpul .300 Blk Mags Now Shipping

Magpul announced this week that they are officially shipping the Gen M3 .300 Blackout magazines. These magazines are specifically designed for efficient and dependable feeding of .300 AAC Blackout/Whisper ammunition into an AR. Though the advantage of the .300 Blk was that it could fit into a normal .223 Remington/5.56 NATO magazine, there are often issues with feeding and being able to fit a full 30 rounds into the magazine. The .300 Blk cartridge is very similar in size to the 5.56 NATO cartridge, but the slightly different dimensions can cause feeding issues. To remedy that, Magpul has created a line of magazines optimized for .300 Blk rifles.

magpul 300 blk

From Magpul:

The PMAG® 30 AR 300 B GEN M3™ is a purpose-designed magazine for rifles chambered in 300 Blackout®. Since its inception, 300 Blackout shooters have had to use a magazine designed for another cartridge, limiting its ultimate performance and compatibility. One of the nice features of 300 Blackout is the compatibility with 5.56x45mm parts, but with the magazine it is a compromise to do so. Due to the wide variety of projectile weights and profiles potentially decreasing overall reliability, a dedicated 300 Blackout magazine was a logical step for the PMAG line.

In addition to the performance gained by a dedicated mag, the PMAG 30 AR 300 B also offers a safer way to feed your 300 Blackout rifle. When using 5.56x45mm mags, the potential to chamber and fire a 300 Blackout round in a 5.56x45mm rifle with catastrophic results requires diligent ammunition management by the shooter. The PMAG 30 AR 300 B’s distinct rib design and smoother upper-half texture provides the shooter a distinct visual and tactile difference from any other PMAG to mitigate dangerous cross-loading issues. Along with optimized 300 Blackout performance, the PMAG 30 AR 300 B brings along all of the GEN M3 features such as our next-generation impact and crush resistant polymer, aggressive front and rear texture, an easily removable slim floor plate, a paint pen dot matrix for marking and identification, and a dust/impact cover.

• The PMAG 30 AR 300 B’s distinct rib design and smoother upper-half texture provides the shooter a distinct visual and tactile difference from any other PMAG
• Dedicated, purpose-designed magazine for rifles chambered in 300 Blackout
• Optimized internal geometry accommodates the wide variety of bullet profiles used in 300 Blackout cartridges
• Carries forward the physical & performance features of the rest of the GEN M3 line

Magpul even released a handy video for those who are more visual learners. Like all of Magpul’s videos, its pretty neat:

Magpul Gen M3 300 B magazines have just started shipping, so we should have some in stock within the next week or two. If you want to get your hands on one, you can click here: Magpul Gen M3 300 B at Defender Outdoors.

You can view our full line of MagPul products here.

Do you think a dedicated .300 BLK magazine is needed? Let us know your thoughts in the comments

5 Comments On This Article

  1. Could we do without this new .300AAC Blackout magazine? Of course, since there is an alternative. The question is really, ‘why should we us the alternative?’

  2. Oh, come on Dave. It’s not like you’ll never buy new mags again.
    You’ll buy them just fine if you have a 300blk.

    I personally have other brands, and i wish magpul made these years ago. I’m guessing they will be top notch.

  3. I wonder how they will work with my 7.62×39 rounds since they[300BO mags] have a larger feed clearance due to the larger projectile. A small modification and I would expect them to assist in feeding rounds more smoothly when the rifle runs hot.

  4. I’ve been using Magpul 5.56 mags for my 300 blackout without any problems . I’ve only been shooting the 125gr but will try the heavier bullets in the near future. I was hesitant about mixing my magazines so I’ve dedicated 4 30 rd mags for my 300 blackout by putting magazine “socks ” from Ultimate Arms Gear . Bought them on Amazon. These can easily be identified even in the dark . If I have problems feeding the heavier bullets I might try these 300 mags.