Model 21 was available in several different styles and configurations:
1. Standard Grade: chambered in 12-, 16-, 20-gauge; barrel lengths 26", 28", 30", 32"; matted or ventilated rib; select walnut checkered pistol-/straight-grip stock; checkered beavertail fore-end. Built from 1931 to 1959.
2. Tournament Grade: same as above; special dimension stock; marked "TOURNAMENT" on bottom of trigger plate. Built from 1933 to 1934.
3. Trap Grade: same as above; slightly better-grade wood; stock made to customers’ dimensions; marked "TRAP" on trigger plate. Built from 1932 to 1959.
4. Skeet Grade: same as above; addition of 28-gauge; stock furnished with checkered butt; marked "SKEET" on trigger plate. Built from 1936 to 1959.
5. Duck Gun: chambered for 12-gauge; 3" Magnum shells; 30" or 32" barrels; Standard Grade stock, except for shorter length of pull; marked "DUCK" on trigger plate. Built from 1940 to 1952.
6. Magnum Gun: chambered for 12- or 20-gauge; 3" Magnum shells; same stock as Duck Gun; not marked on trigger plate. Built from 1953 to 1959.
7. Custom Built/Deluxe Grade: chambered for 12-, 16-, 20-, 28-gauge and .410 bore; barrel lengths from 26" to 32"; stock built to customers specifications using fancy walnut; marked "CUS­TOM BUILT" on top of rib or "DELUXE" on trigger plate; these grades are frequently, but not always engraved. Built from 1933 to 1959.

NOTE: Some early Model 21s furnished with double trig­gers, extractors and splinter fore-ends. This combination reduces price of the gun regardless of grade. Deduct about 25 per­cent.