NEW .300 AAC BLACKOUT CARTRIDGE NEW .300 AAC BLACKOUT CARTRIDGE
There has been some chatter on the internet forums regarding a new cartridge for the AR15/M16 platform. Our ballistics guru Laurie Holland finds out more...
Read up on US military smallarms development since smokeless cartridges replaced the big-boomer 45-70 Government and you’ll soon be confused. For much of the last century, American policymakers had a love-affair with big, full-power thirty calibre numbers starting with the 30-40 ‘Krag’, seeing a couple of world wars and several generations of soldiers through with the famous .30- 06 Springfield and finishing up with 7.62X51mm NATO or .308 Winchester.
Twice the establishment killed off smaller calibres in lighter cartridges and rifles. The first time was in the 1930s when US Army Chief of Staff Gen. Douglas Macarthur told Springfield Armory and John C. Garand that the new M1 self loading rifle would be chambered in 30-06, not 276 Pedersen (7X51mm) as envisaged by the boffins and more progressive soldiers. Then just after WW2, the US Army ordnance establishment killed off the Anglo- Canadian-Belgian 280/300 British (7X43mm) project as the basis of the proposed NATO standard assault rifle and cartridge.
by Laurie Holland
The alternative US T65E3 which became the 7.62mm NATO/308 Win was much larger and more powerful than its contemporary Soviet 7.62X39mm M43 rival that allowed the Russians to develop and manufacture the world’s most successful assault rifle by far, the AK47 and its derivatives. As a result, NATO forces were stuck with long, heavy rifles that had to be permanently locked on the semi-auto fire setting as the 7.62’s recoil and heat production were excessive for full-automatic.
Then came the 1960s, Vietnam and Gene Stoner and within an amazingly short period of time, the USA performed a perfect U-turn adopting the 22 calibre (5.56X45mm or 223 Rem in civilian guise) AR15 as the M16A1 and terminating its 7.62mm M14 rifle procurement programme in mid flow.
Within a few more years, the USA had decided to standardise on the M16 in an improved A2 model optimised for a heavy (62gn) bullet version of the 5.56mm cartridge and a host of specialised spin-offs such as the M4 Carbine have since appeared. Her NATO partners were dragooned into replacing their self-loading 7.62s for a new expensive generation of 5.56m assault rifles and squad support weapons (light and GP machineguns).
In its 61.7gn twin-core bullet M855 guise, the 5.56mm cartridge has more than enough effective range for all normal infantry engagements, but there has been a long running undercurrent of dissatisfaction with the small calibre bullet’s lethality or knock-down ability. This particularly applies to shorter barrel weapons such as the M4 Carbine and specialised quasi sub- machineguns used by special forces. Lethality was fine, frighteningly so in fact, in the short range heavy cover fire-fights US forces saw in Vietnam but the open spaces of Afghanistan and Iraq have provided very different experiences for a later generation of soldiers and marines, especially with short barrel, hence reduced velocity, carbines in specialised
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