I'm looking for an unported 31.5" Perazzi MT6 Type 4 barrel that accepts chokes with threading near the knurled end. I've got a ported 31.5" Perazzi MT6 Type 4 barrel that accepts chokes with threading near the knurled end. I've also got a 28 3/8" Perazzi MT6 Type 4 barrel that accepts chokes with threading near the bottom of the chokes. Both of the above barrels will fit any Type 4 Perazzi O/U, including MX8, MX12, MX2000, MX2000S, etc.