The 155gr 300BLK handloaded round Dan used was built with Remington brass in the AMU shop, as was the USAMU Custom Firearms Shop 20" 1:12 twist upper with an extended JP handguard seen winning above. It's topped with a Swarovski Optik 1 - 6 x power optic.
The win for 300BLK is significant because it shows a use for the round outside of clearing rooms in unfriendly nations. 300BLK allows shooting sports competitors to use the lightweight and ubiquitous AR platform to compete effectively against heavier, higher caliber guns.
4 years ago, the US AMU started looking at a .308 carbine round so they could make major power factor in shooting sports competition. This is something that 5.56 can't do. Blame physics. PF is the rounds weight multiplied by it's speed. Making major power factor is important because of the way USPSA scores contestants based on the stopping power and recoil of the rounds they use. Major power factor shooters scores are weighted more than minor power factor shooters.
The AMU first tried 300 Whisper as their entry into the major power factor. But, they found it was difficult to get the .308 round moving fast enough to make major safely with the Whisper solution. They wanted to keep to SAAMI specs for chamber pressure and the Whisper formula had to be heavily tweaked to get there. The arching trajectory of the round was also a concern.
They next looked at the 6.5 Grendel case and found they could neck it up to 7.62, giving them the round they wanted at a safe chamber pressure. In fact, the 30AS (or 30 Gremlin as it's also known), is a solid shot out to 600 meters, has recoil similar to a 5.56, and makes major power factor in competition. It's become the AMUs go-to round for action shooting. But, the round has an Achilles heel; magazine compatibility. The unit must make its own mags and the most 30AS ammo that will fit in a standard AR mag body is 26 rounds; though they've managed to get to 37 rounds with extended floorplates.
For this reason, AMU members have looked back at the 300 Whisper concept and it's standard magazine compatibility wistfully. As soon as they too a fresh look at load recipes and recognized that Remington's standardized 300BLK components could get them safely up to major power factor, they brought it in.
The 300BLK's trajectory is still on the round side for really long ranges, being most effective out to 300 meters-- but it's clearly fine for USPSA style competition. The AMU still uses the 30AS for any gun games that present more distant targets, like outlaw shooting events. But, inside 300 meters, the 300BLK is the right combination of power and compatibility to get the job done. And done well.
Congratulations to Daniel!
(Photo Courtesy USAMU)
