Bartlein - SS, 6mm (.237), B#4 Bull Sporter, 7.5 twist, 27" blank CF WRAPPED (26" finish), 5R

Bartlein 6mm B#4 Bull Sporter Barrel Blank

The Bartlein 6mm B#4 Bull Sporter is a match-grade carbon-fiber-wrapped stainless steel barrel blank, cut-rifled and hand-lapped by Bartlein. It runs a 1:7.5" twist with 5R ratchet rifling and ships as a 27" blank, ready to chamber, contour, and crown to your spec.

Specifications

• Caliber / bore: 6mm
• Contour: B#4 Bull Sporter
• Twist rate: 1:7.5"
• Blank length: 27"
• Rifling: 5R ratchet rifling (5 grooves)
• Material: Carbon-fiber-wrapped stainless steel, hand-lapped

Is this the right barrel for your build?

This is a fast twist, best suited to the heavier, longer, high-BC bullets favored for competition and long-range work. It's a target-weight contour that adds mass toward the muzzle to steady the rifle and help it hold zero as the barrel heats. The carbon-fiber wrap sheds weight while keeping the stiffness of a heavier profile and dissipating heat well — popular for PRS and mountain builds where weight matters. Not sure it's right for your action, chamber, or bullet? Tell us what you're building and we'll help you get it right.

What a barrel blank is

A barrel blank is finished to your spec: your gunsmith cuts it to length, chambers it, threads the tenon to your action, and crowns the muzzle. Cutting a blank to length doesn't change its twist rate, so order for the finished length and profile your build calls for.

Keep it shooting

We recommend pairing your barrel with the ThorroClean Bore Cleaning System — fast, odorless bore cleaning that helps protect accuracy and keep the bore in top condition.