From The Military Times site
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Calibers come and go, but not usually from companies that are tied into military contracts.  With the M4 replacement testing coming up in the near future, we weren’t surprised when we got a call from AAC/ Remington telling us about a new project.  What we didn’t see coming was that sneak peaks would be done at Modern Day Marine.  Luckily, we were on hand as Marines in the know petted and panted over the pumped up SBR.
As interesting as a new caliber is to some of us, it gets better.  Start thinking about a M4 with a 9″ barrel that has  37% more energy than 5.56mm M855 from a 16″ barrel (the standard M4 is a 14.5″).  Clearing buildings, crawl spaces, vehicle work, going up ladders and seizing ships or aircraft are all tasks that have us wanting a short barrel, but getting shot at has us wanting a round that ends threats quickly.  It looks like the new 300 AAC Blackout from Remington/ AAC ammunition and upper receiver is at the right place at the right time.


We spoke with Robert Silvers who is the Research and Development Director for Advanced Armament Corp.  Mr. Silvers explained that they had developed not only a caliber, but also an upper receiver group that would drop on existing M4 carbines (or AR15s).  This upper receiver group uses a standard  M4 bolt and Bolt Carrier Group (BCG).  We pointed out that this allowed for an immediate swap for Military or Law Enforcement teams that were already using the M4 as all they would need would be for their armorers to change out barrels.  I don’t think my observation was anything new, and he agreed.  He went on to state there were three types of SAAMI approved ammunition immediately available with additional options coming up in the near future.
Current ammunition types are the 123 gr. MC 300BLK, 155 gr. OTM 300BLK, and 220 gr. SUBSONIC OTM 300BLK.  Each round is purpose driven, and allows selection for a given mission.  The supersonic ammunition was developed as a 5.56 replacement, while the heavier subsonic ammo was designed to give a total weapon replacement option for users of the MP5 and MP7.  Barrier Blind Optimal Penetration ammo is currently under development.
One weapon and caliber replacing the standard M4, AND the more specialized HK MP-5 and HK MP-7A1?  It sounds like a congressman or city managers prayers have been answered, never mind unit armorer and supply guys.  Money issues aside, training with one weapon platform makes more sense than jumping back and forth.  Of course we use the best tools available for the job, but sometimes less is more.
Advanced Armament Corp is best known for their suppressors, and it makes sense that along with the development of the upper and ammunition, a silencer would be included.  The numbers given to us show the new 762-SDN-6 suppressor is shooting a 220 grain 300BLK bullet at 1000FPS at 126.2 dB.  The  MP5-SD is firing a 115 grain bullet at 900FPS at 130dB with its HK suppressor.  I understand that these numbers were not done at the same time, and that various testing methods can show different results, so I look at these as rough numbers.  Anyone who had fired a suppressed MP5 knows how quiet they are, so even as a ballpark figure, these numbers are impressive.
Below are the listed design objectives as they were given.  When I asked who had come to AAC/ Remington with these design objectives, I was met with a moment of silence, and told it just came as part of a project.  Fair enough.
DESIGN OBJECTIVES
• Create a reliable compact 30-cal solution for the AR platform
• Utilize existing inventory magazines while retaining their full capacity
• Create the optimal platform for sound and flash suppressed fire
• Create compatible supersonic ammo that matches 7.62×39 ballistics
• Provide the ability to penetrate barriers with high-mass projectiles
• Provide all capabilities in a lightweight, durable, low recoiling package
Mr. Silvers pointed out several times that this was not a caliber that was exclusive to the Military or Law Enforcement market.  His stated his goal was to be able to deliver a reliable source of ammunition through Remington, and to make the 300 AAC Blackout something affordable for target shooters and hunters.  There are a lot of AR15 shooters in this country, and a lot of hunters, but most states will not allow hunting with a .22 caliber.  The advent of the 300 AAC Blackout may bring interest from a few other avenues as news of this circulates throughout the shooting community.  While 6.8SPC is an option, there many people who will like the ability to use their current AR15 magazines, as well as using a standard 5.56 bolt.  Ammunition reloaders may find their .30 favorite bullets another reason to look at the 300 AAC Blackout.
There is a lot more information that we have on this weapon system, but we have one in hand, and ammunition enroute to us.  We are going to put the weapon and rounds in the hands of MIL and LE trigger pullers, then report back with our findings.  For now, check out the new website and start soaking it all up.

I didn't have the ammunition on hand when I wrote the article, so I couldn't take any pictures of it.  When I get the ammunition, and write up an evaluation based on live fire usage (including FA & Suppressed), I'll include more images.


My understanding is that barrels are in the works.  There is no need to buy a complete upper unless you don't want to rebarrel one of your existing ones.

I read the original post and was thinking 300 whisper............sure enough, it basicly is a 300 whisper.........wow, someone reinvented the wheel and it is still round. you do not need much case for subsonic.......x25mm will get the 200 and 220 grain projectiles running subsonic with no problems..............so 5.56 brass can now be formed to this case also.

Hm, interesting. I've been kicking around getting a 338spectre, but it's just a lot of trouble. This looks like it's going to get some serious backing under Remington Arms. Also appears to be a pretty versatile loading range.



I wonder what the parent case is, looks like dies are already online for reloaders. With just a barrel swap, this could be a good deal.