I'll go with the guys on the Brownells sets. I'd add too the bit holding gizmo for the grinding that is sure to happen sometime. I know you can do it freehand and I have, but the gizmo is just the really proper way to do it -


Of course if you really want to do it the old way, get a couple leaf springs from the auto wrecking yard and start cutting. Recommended method in an old Limey gunsmithing book I have.
Bonne chance

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