Roughcut Picatinny Grip

A roughcut grip with a picatinny rail built into the base of it, allowing one to use any grips or attachments that fit onto said rail.

I would suggest using 2 M4x40 screws, though that's only a guess as I don't have any of that length currently. Technically you can get away without screws but that requires a grip to be tightly mounted onto it at all times.