Question: is there a difference between 300 blackout and 300 aac blackout

Answer: No, 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.