The 300BLK is designed to provide a compact .30 caliber solution to the AR platform and has quickly become a much sought-after round by military and commercial markets. It utilizes existing magazines and features minimal recoil while still packing the punch found in a heavier .30 caliber round.

Capable of supersonic and subsonic performance, the 300BLK has much to offer military and law enforcement operations. The round’s versatile performance has earned it notoriety in the sportsman’s market as a great option for hunting medium-sized game.

Drawn from American-made premium brass cups, each casing undergoes rigorous in-line and post-production quality assurance testing to ensure a flawless casing of unparalleled durability and dependability.

Standard casing dimensions and tolerances have been modified to achieve maximum performance. Jagemann™ Technologies’ in-house tooling and engineering capabilities provide the ability to customize casing dimensions for use with specific projectiles. If you have a custom request, we will meet your needs.

Contact us for more information.


Type: Military/LE, Personal Defense, Sporting

Date of Origin: January 17th 2011 (parent case is 221 Fire ball/.223 Rem)

Case Type: Rimless, Bottleneck

Neck Diameter: .334 in (8.5mm)

Shoulder Diameter: .3607 in (9.1617mm)

Base Diameter: .376 in (9.6012mm)

Case Length: 1.368 in (34.7472mm)

Primer Type: Small Rifle Primer

Max Pressure: 55,000 psi


5757 West Custer St.
Manitowoc, WI 54220


(800) 998-6901




Have a stamping design or engineering request?