Spanner nut to be 1.275" below magazine tube cap with 26" barrel, cutt's type poly-choke.
Test fire and adjust as neccy.
1. lower, "increased dimension" equals more gas to cycle (harder hit in receiver,not good).
2. Higher, "decreased dimension" equals less gas to operate action and will result in short stroking.
Gas system components MUST be clean and DRY, NO LUBE of any kind .
Very nice shotgun. My favorite, even over an 1100 Remington.
The address of the Rolette Public Library is: 1015 1St Avenue, Rolette, 58366 0175