<Tr> <Td> 90 gr (6 g) Barnes OTFB </Td> <Td> 2,550 ft / s (780 m / s) </Td> <Td_colspan="2"> 1,300 ft ⋅ lbf (1,800 J) </Td> </Tr> <Tr> <Td_colspan="2"> Test barrel length: 16 in </Td> </Tr> <P> The . 300 AAC Blackout (designated as the 300 BLK by the SAAMI and 300 AAC Blackout by the C.I.P.), also known as 7.62 × 35mm is a carbine cartridge developed in the United States by Advanced Armament Corporation (AAC) for use in the M4 carbine . Its purpose is to achieve ballistics similar to the 7.62 × 39mm Soviet cartridge in an AR - 15 while using standard AR - 15 magazines at their normal capacity . It can be seen as a SAAMI - certified copy of J.D. Jones' wildcat . 300 Whisper . Care should be taken not to use 300 BLK ammunition in a rifle chambered for 7.62 × 40mm Wilson Tactical . </P> <P> While 5.56 × 45mm NATO has enjoyed widespread acceptance in military circles, the nature of the missions encountered by some special operations groups often demand a round that provides better performance than that available in the high - energy standard velocity rounds and subsonic performance greater than standard 9mm (the ubiquitous pistol round also commonly used in many SMGs). </P>

Is there a difference between 300 blackout and 300 aac blackout