Iver Johnson Mobil Choke Tube Features The Iver Johnson Mobil Choke Tube in a rifled configuration is designed specifically to improve accuracy when shooting sabot style slugs out of a 20 gauge shotgun. The rifling inside the tube imparts spin on the slug as it exits stabilizing it in flight much like a rifled barrel would for a bullet. This stainless steel construction stands up to the elevated chamber pressures and repeated firing that slug hunting demands without corroding over a season of use. The Mobil style threads allow this tube to install directly into compatible shotgun barrels already cut for that thread pattern. An extended design projects past the muzzle making the choke easy to spot and hand tighten in the field without needing a dedicated choke wrench. That same extended profile helps shield the barrel s threaded section from dirt and moisture during storage between hunts. Iver Johnson manufactures this choke to Mobil specifications giving shooters a drop in upgrade path for improving slug performance on an existing 20 gauge shotgun. This rifled Mobil choke tube from Iver Johnson is available for sale at GrabAGun for hunters chasing better slug accuracy in slug-only hunting zones. Iver Johnson Mobil Choke Tube Specifications Manufacturer: Iver Johnson Model: Mobil Choke Tube Caliber: 20 GA Choke Type: Rifled Profile: Extended Material: Stainless Steel Thread Pattern: Mobil Available At: GrabAGun