
Very rare and VERY expensive. That’s how I would sum up this twenty gauge side-by-side. It was made in 1936 by London’s Boss & Co, and it has several features which add up to make it an exceptionally rare British shotgun:
- Barrel length: 28″ tubes are hard to find in smallbore Bosses
- Original 2 3/4″ chambers: Most 20 gauge Bosses (and British shotguns) have 2 1/2″ chambers
- Original 1 ounce heavy proofer: Most are proofed for 7/8 ounce loads
- Genuine self opener: Boss may have built 60-70 self-opening SxSs in all. Most were 12 bores.

Here’s more info about the gun from the seller.
PRE-WAR BOSS 20GA SIDELOCK SXS GAME GUN: Fantastic original pre-war Boss 20 bore game gun. 28” nitro-proof steel barrels with game rib. Original 2 ¾” chambers. Ejectors. Case-colored sidelock action with classic rose & scroll engraving. Double triggers. Fabulous black-streaked English walnut straight grip stock and splinter forend. Leather case with maker’s label and accessories. Price: $89,500
Model: BEST SIDELOCK GAME GUN
Bore: 20
Chambers: 2 3/4″

Ejectors: YES
Condition: EXCELLENT
Metal Condition: EXCELLENT
Wood Condition: EXCELLENT
Bore Condition: BRIGHT
Barrels: 28″
Barrel Type: STEEL
Action: SIDELOCK
Triggers: DOUBLE
Gauge: 20
Stock: ENGLISH WALNUT
Stock Dimensions:
STRAIGHT GRIP

Stock Comb: 1 3/8″
Stock Heel: 2 1/4″
Stock Cast: 1/8″
Fore End: SPLINTER
Butt Pad: CHECKERED BUTT
LOP: 14 3/4″
Rib: GAME
Finish: BLUE
Weight: 5LBS 14OZ
Manufacture Date: 1936
Choke Left: .020
Choke Right: .011
Engraving: ROSE & SCROLL
Case: LEATHER FACTORY CASE
Proof:Nitro: YES
Minimum Wall Thickness Left: .029″
Minimum Wall Thickness Right: .030″