On the .300 BLACKOUT……perhaps the perfect battle rifle…..

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….On the .300 BLACKOUT

perhaps the perfect battle rifle…..

            I missed the punch and reach of my 7.62 M-14 from the very first day that I had to trade it in for an M-16. I received an early M-16 in Vietnam and it was plagued with all of the horror stories you have heard. My main complaint was after running about 100 rounds through it; carbon blew back, fell into the lower receiver and locked up the selector switch on “SAFE”. It had to be dis-assembled and cleaned to correct the problem. I was not happy with it. I very shortly traded it for a 1911 and a 54 ton mono-pod for a sky mounted M-60.

            Despite my bad experience with the M-16, I later learned a bit more about the Armalite/Colt AR15 system and its inventor Eugene Stoner that led me to buy a 5 digit # Colt SP1 carbine with collapsible stock for $400 (Yeah don’t you wish!) I tricked it out a little and shot many rifle assault courses with it. It always performed very well, but still I missed the knock down power and reach of that.308 cal. Round.

            Many people tried to marry the AR system to the AK system to get the best of both worlds. I looked at many of them.  None were very successful. There was always a problem: custom bolts, magazines, barrels/chambers, ammo etc. were required. The options were the Galil by the IMI/ IDF but that was still .223, or find a limited production AR10 (licensed to Portugal and used in the Congo) and spend a fortune for what was essentially a big ugly gun with bulbous muzzle and large heavy magazines.

            I gave up the search many years ago….until the .300 BLACKOUT appeared. The whole concept of this rifle was one of those “It’s so obvious! Why didn’t I think of this?”

300 AAC Blackout1

            The .300 BLACKOUT round is a cut down (at the shoulder) .223 brass case, re-necked and sized for a .308 projectile from 110 to 245 grains. The nature of the cut down and OAL allows the use of ANY AR15 platform magazine with no alterations and full capacity. I won’t go into its performance (Google it) suffice it to say that it works great with light supersonic bullets (2369fps@0.67 in.) as well as heavy weight sub-sonic bullets (1287fps. @0.35 in.) that fire almost as silently as an H&K MP5SD while using a can. The BLACKOUT will also fire .300 Whisper ammo. .223 brass is readily available for reloading.

All AR accessories also fit the BLACKOUT rifles; as other than the barrel and chamber there is no difference in the two platforms. When Remington started to produce factory ammunition for the BLACKOUT its popularity and availability widely expanded. .300 BLACKOUT ammunition is now available (or will be soon) from at least eight manufacturers

You can now purchase: barrels; to up gun your current AR, complete rifles or uppers in many configurations from at least 10 manufacturers. Guns & Ammo devoted an entire issue to this rifle. It is a viable, working, and available .308 caliber AR system that minimally requires only re-barreling: magazines, bolt and bolt carrier all remain the same.

CMMG .300 Blackout upper on SP1 lower w/flip up iron sites and HOLO site on left.
CMMG .22LR Cal.BCG conversion in center.
Colt SP1 5.56mm upper w/Barska 3-9×50 IR scope

I’m pretty much old school, and like old retro guns, but just the same Magpul co. has its attraction to me and I was excited by this new upper. I shopped a new Magpul OD green forearm, collapsible butt stock and some flip up iron sites. I also ordered a Miculek compensator that is almost an exact match of my Umberger comp on my .223 upper, and dug out a new crush washer. I have a whole collection of optics to drop on from a simple reflex dot site, ranging 3-9×50 IR scope, to a Gen 3 NVD. Which upper will get what configuration remains to be seen. I still have an original Colt 4X scope for the carry handle .223 upper.

There are two problems with this conversion. The first is peculiar only to my very old SP1: The upper and lower both use a 5/16” pivot pin. Modern uppers (after about 1975) use a ¼” pin front and rear. This required a 48 hour search to find an eccentric pin that I remembered that Choate Machine and Tool offered many years ago. I found one from DPMS for about $3. Problem solved the upper and lower would now happily mate..

The second problem is much more severe. This is a SAFETY ISSUE! The nature of the .300 BLACKOUT using a cut down .223 cartridge means that you can inadvertently chamber a .300 BLACKOUT round in a .223 rifle or upper. The bullet will push back into the cartridge upon chambering and on firing it will feed you parts of the receiver and BCG. Not a good thing. As the same magazines can be used with either system, It would probably be a very good idea to dedicate certain magazines just to your .300 BLACKOUT and paint them or better yet alter their surface so that you can feel the difference. Perhaps an inner tube band around the base or different floor plates.

I have yet to fire this newly configured monster, I have plenty of .308 bullets, small primers, and can cut down my cases but the powder I needed is still unavailable due to the panic. Big surprise, I found a can of IMR 4227 stashed away. Looks like I will set up the Lyman press and put together a few rounds for a test.

If you have been planning on adding a .308 to your battery but were dissuaded by the cost, you might consider a .300 BLACKOUT upper at half the cost.

Regards, D.

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  1. Nice Blackouts! I built two from 80% lowers. Both have AAC built uppers. One is an 8.5″ flat top pistol upper, and the other is a 16″ upper both with knights KAC free float tubes. I LOVE these guns! I have a regular 5.56 AR, but it does not have anywhere near the knock down power of the .300.

    NOW, My big question…..where the heck do you get your ammo? I have had such a hard time finding ammo its not even funny. IN fact, I can usually only get .300 whisper which is basically the same. I actually went and ordered a reloading kit and dies to reload my own and cut down 5.56 brass for the Blackout.

  2. Gary:
    You are right, no ammo but some Whisper out there. Components are even hard to find. Buy the dies with it! It is a commitment to the caliber.
    I’m loading my own. Luckily I found a old can of IMR4227 in my stash.
    Get a cut off saw from Harbor Freight ($38 much faster)and start prepping your old .223 cases. It’s tedious, but once you’ve got some together hang onto them.

    I have since had a chance to shoot a few (16.5 grns IMR4227 in back of Nosler 125 grn.ballistic tip) I’m impressed. I will be loading and trying out some heavier bullets as my brass collecion grows.

    I have addressed the safety issue by dedicating some Pmags with ranger base plates solely to the Blackout. Those mags will not get near a .223 rifle, and no other mags will receive those base plates.
    Good luck with your reloadng. It’s the only way to go in grid down.
    Regards, D.

  3. I guess I lucked up. I first bought a Bushmaster AR15. Don’t know why, I hated the M16 in Vietnam. Later, I found out about the AR10 from Armalite. I bought 2. Now that is a real firearm! I love it. Reloads are easy and the rifle is a joy to shoot. I’ve had some tell me the recoil is punishing, but frankly, I find it no more than the 16.

    This is the first I’ve heard of the .300. I’ll definitely look into it.

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