Defender Ammunition Company & Rock River Arms X Series .300 BLK Review

Rock River Arms sent their X-Series .300 Blackout rifle for testing and review. In initial testing we had issues with the Rock River Arms X Series .300 AAC Blackout rifle […]

Rock River Arms sent their X-Series .300 Blackout rifle for testing and review. In initial testing we had issues with the Rock River Arms X Series .300 AAC Blackout rifle short cycling when shooting our custom subsonic loads. This effectively made it a bolt action rifle. The other two .300 Blackout ARs in our test inventory, a pistol and 16″ barreled rifle, both from Radical Firearms, and both what we consider to be basic, budget ARs, worked flawlessly with our homebrewed subsonic rounds. Not what we hoped for from the relatively high-end RRA X-Series.

Defender Ammunition was kind enough to send us a couple of boxes of Supersonic and Subsonic .300 BLK remanufactured ammo. So, we headed to the range on a rainy day to try the X Series with Defender Ammunition Company‘s Supersonic 150 Grain and 220 Grain Subsonic .300 AAC Blackout rounds.

We are quite pleased to report that the Rock River Arms X Series rifle cycled flawlessly with both the supersonic and subsonic rounds from Defender Ammunition Company. The ammo fed smoothly from the ProMag Roller Mag with ARCustoms.com AR Soc and the Hexmag.
Here is the video…


With subsonic ammo cycling demonstrated we are getting closer to wrapping up the full review for the Rock River Arms X-Series rifle.

About Jeff

Jeff is the Editor in Chief of Gear Report and a National Shooting Sports Foundation Media member. He reports on the outdoor industry, reviews gear for camping, hiking, shooting, hunting, paddling, backpacking and other active pursuits. A USAF veteran, Jeff earned a MBA in Marketing and Health Services. He specializes in consultative selling and internet marketing. As the VP of BD & Marketing, Jeff provides sales and marketing leadership to MGECOM, Inc. and helps http://MGECOM.com acquire new clients in need of solutions for online merchants in need of Affiliate Marketing program management. Jeff founded and manages Cress Sales & Marketing LLC, offering online sales and marketing consulting and services to online merchants and service providers.