This is new 300 AAC Blackout ammo with 147 gr FMJ bullets w/ cannelure. All components are new and the headstamp says MAST 300 BLK. These are not re-purposed cases The average velocity is 1900 FPS. This ammo contains a Mil-Spec #41 Small rifle primer and the use of a traditional bolt gun could result in misfires due to the thicker cup primer.
Note: This ammo has been tested in a 16″ Carbine length gas system. Any other configuration to include SBR’s and the use of suppressors could have different results.