Bartlein - SS, 7mm, B# Custom, 8.5 twist, 21" blank (20" finish), 5R

Bartlein 7mm B# Custom Barrel Blank

The Bartlein 7mm B# Custom is a match-grade stainless steel barrel blank, cut-rifled and hand-lapped by Bartlein. It runs a 1:8.5" twist with 5R ratchet rifling and ships as a 21" blank, ready to chamber, contour, and crown to your spec.

Specifications

• Caliber / bore: 7mm
• Contour: B# Custom
• Twist rate: 1:8.5"
• Blank length: 21"
• Rifling: 5R ratchet rifling (5 grooves)
• Material: Stainless steel, hand-lapped

Is this the right barrel for your build?

This is a mid-range twist that stabilizes a broad spread of bullet weights — a versatile choice for target and field builds. The contour balances weight and stiffness for a steady, consistent hold. 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.