SIG Sauer has announced a new addition to its nascent ammunition line: Supersonic .300 Blackout. Loaded with 125gr Sierra MatchKing projectiles, this load rounds out the SIG-branded .300 Blackout for their MCX rifle. From the press release:

Newington, NH – SIG SAUER, Inc., designer and manufacturer of the world’s most reliable firearms, accessories, and ammunition, is pleased to announce its new 300 Blackout Supersonic Elite Performance Ammunition Match Grade Centerfire Cartridges. This supersonic round features a 125gr Sierra Matchking projectile and, like the SIG SAUER 220gr subsonic 300 Blackout round, is designed to bring out the best in today’s high-performance AR rifles.

The Sierra Matchking projectiles in the 300 Blackout supersonic rounds are renowned for their superior accuracy, flat trajectory and consistent point of impact. The unique hybrid hollow point bullet design also ensures maximum expansion on point of impact. These cartridges feature match grade brass cases and function with standard 223Remington/5.56mm magazines without a reduction in capacity.

“The 300 Blackout is an increasingly popular caliber with target shooters and 3-gun competition shooters, and is also an excellent round for home defense in short barrel rifles, including the SIG MCX and M400,” said Bud Fini, vice president of marketing for SIG SAUER. “Elite military units are also evaluating the 300 Blackout as their primary CQB load. More modern sporting rifle hunters are turning to the 300 Blackout for close-range hunting of mid-sized game, including hogs and deer. We are pleased to now offer our customers both supersonic and subsonic rounds to meet their shooting and hunting needs.”

All Elite Performance Ammunition is manufactured in the United States by SIG SAUER to the same exacting standards as the company’s premium pistols and rifles. For more information, visit www.sigsauer.com/ammunition.

.300 Blackout in its supersonic form is ballistically very similar to the old 7.92×33 Kurz round, both in energy and trajectory. The primary ballistic difference lies in the very long ogive, necessitated for proper feeding from AR-15 magazines originally designed for longer-cased 5.56mm ammunition.