Choke tubes frozen in place from expansion is different from rust or residue build up. However rust, residue build up and choke expansion can all occur at the same time.
Source: What Causes Shotgun Choke Tubes To Lock Up Or Freeze In The Barrel?
Choke tubes frozen in place from expansion is different from rust or residue build up. However rust, residue build up and choke expansion can all occur at the same time.
Source: What Causes Shotgun Choke Tubes To Lock Up Or Freeze In The Barrel?