Black River Manufacturing SBS Benelli M4 12 Gauge Shotgun Barrel 14 in Chrome Linded Gray. ALL NFA RULES APPLY. Black River Manufacturing barrels are drilled from 4140 steel instead of 4130 which has nickel in it which makes it softer. 4130 is used because it can be extruded to make barrels to cut down on costs leaving you with a low quality barrel. Theirs are drilled from 4140 to ensure the highest quality possible. Specifications for Black River Manufacturing SBS Benelli M4 12 Gauge Shotgun Barrel: Manufacturer: Black River Manufacturing Finish: Chrome Linded Fabric/Material: 4140 Steel Barrel Length: 14 in Gauge: 12 Gun Make: Benelli Gun Model: Benelli M4 Gun Type: Shotgun Package Contents: Black River Manufacturing SBS Benelli M4 12 Gauge Shotgun Barrel What firearm models does the manufacturer say Black River Manufacturing SBS Benelli M4 12 Gauge Shotgun Barrel is compatible with? The manufacturer says that Black River Manufacturing SBS Benelli M4 12 Gauge Shotgun Barrel is compatible with Benelli M4Black River Manufacturing BRBMPBGRSBS: SBS Benelli M4 12 Gauge Shotgun Barrel 14 in Chrome Linded Gray