
The sidelock, double-barrel over-under shotgun you see here is one of the holy grails of British shotguns — and one of the mysteries of British gunmaking. It’s coming up to auction tomorrow, 10/17, and it has an estimated hammer of $25,000.00 – $50,000.

Boss & Co. patented their OU action in 1909. According to the company’s website:
“Robertson did not invent the O/U shotgun, but he created an Over and Under gun that was elegant, shapely, strong and far lighter than any other on the market. Until that time Over and Under guns often hailed from Germany but were heavy and ungainly. But Robertson’s OUs were strong, lively, light and slender, marking the Boss & Co Over and Under as the best on the market as soon as it was introduced. Immediately it set the standard and became the benchmark, a celebrated design that remains unsurpassed.”

Since 1909, Boss & Co. has built around 600 over-under shotguns. Very, very few of them were built with a feature that’s on the gun being auctioned off tomorrow: A Boss-style rising-bite action.

No one knows how many OUs Boss built with its rising-bite style action. The feature appears around 1920 and shows up on 12-gauges and 20-gauges through the ’30s (here it is on a gun they built in 1937). I’ve never seen it on a Boss OU built after WW2 (Note: Boss & Co just started building rising-bite actions again and completed one in the last year or so).
But Boss never patented their version of the rising bite. I’ve never seen any evidence that the company promoted this feature or offered it as an upgrade or an option. From what I can tell, it just appears on certain guns and then disappears.
One thing to note: While this gun was originally nitro-proofed with 2 3/4″ chambers for 1 1/4 – ounce loads, it wasn’t made to shoot modern, high-pressure/high-velocity shells. So if you buy it, do the gun a favor and use ammo like this.

Lot #110: Boss & Co. Best O/U 12ga Shotgun: One of England’s finest… Desirable, elegant, made for a shooter. This shotgun has simple lines yet elegant and exceptionally designed side lock. Currently, Boss & Co. only produces about 20 shotguns annually. This one was manufactured in 1919-1920, and proofed for modern shells. Solid rib barrels have a single silver bead front sight, marked with proofs, Nitro proofs and more near breech. Forend is highly ornate with metal side skirts along the back half of the top, engraved with a tight scroll and finely blued. Barrels mate with the hinge pin and special locking mechanism near top lever. Locks are engraved 1005 with fine English scroll. Top lever and trigger are blued and equally ornate. Case coloring is accented with lock pins in both a polished or bright blue. Chamber indicators have horizontal gold inlay. Auto ejectors are crisp and timed superbly. Auto safety. High grade straight English stock with oil rubbed finish completed with a checkered butt and metal plates protecting heel and toe. Choked “Full” and “Mod”, ideal for clays or pheasant. Includes original leather bound case, Boss & Co. label on inside. Factory accessories. Must ship to FFL or C&R Condition: Antique Excellent. Bluing is in the 90-95% with the loss in touch points only (lower tang, forend, top lever, etc.). Case coloring is around 40%, fences and transition areas exhibit fine color striations while side of locks is muted. Wood is excellent, hard to find imperfections, probably cleaned at some point. Mechanically excellent. Barrels and Bores are nearly blem free and mirror bright. Gun Measurements: Chamber size is 2 ¾” Bore Diameter: Over Barrel – From 9” at the breech .733, 12” from the breech is .731 and continues at .731 until it hits the choke and final measurement at muzzle is .714 giving it a “Modified” choke. Under Barrel- From 9” at the breech .7325, 12” from the breech is .7315 and continues at .7315 until it hits the choke and final measurement at muzzle is .694 giving it a “Full” choke. Barrel Wall Thickness: Over Barrel- 12” from breech is .038, 12” from muzzle is .033 and is consistent through to muzzle Under Barrel- 12” from breech is .039, 12” from muzzle is .033 and is consistent through to muzzle LOP @ Heel= 14 7/8″ LOP @ Toe= 15 1/4″ Choke: O=.709 (Mod) U=.689 (Full) Drop @ Comb = 1 1/2″ Drop @ Heel = 2 1/8″ Weight= 7.4 lbs Cast Neutral Barrel Length: 30″ Serial: 6605 Manufacturer: BOSS & CO., LTD. Gauge: 12ga Year-Range 1919 – 1920. Estimate: $25,000.00 – $50,000.00 USD

