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Boss & Co. 20g Hammerless Side by Side

Serial Number 7937



Truly superb between-the-wars Boss & Co. 20g Hammerless Side-by-Side Game Gun. Completed in 1932 and based on John Robertson’s hammerless sidelock ejector developed around 1890.

The Boss & Co. side-by-side is a bar-action sidelock with intercepting sears, disk set strikers, gold-lined cocking indicators, and a patented automatic safety with the word "SAFE" in gold. The guard bow has a rolled edge. The gun also features Boss & Co.’s landmark non-selective single trigger, patent no. 22894 of 1894, and a swept trigger shape which was also a Robertson development, provisional patent 11400 of 1905. This trigger shape was based on the theory that the trigger is pulled to the back and side rather than straight back, therefore the Boss single trigger is swept and pulled obliquely. Today, this is a standard shape on best quality, single triggers of all makes and models. 

It is the wonderful proportions and how expertly the guns were crafted, that make Boss & Co. guns from this era so desirable. This is especially evident in the sub gauge guns made during this same time period. The diminutive size of the action is beautifully scaled for the 20 bore, closer in size to other maker's 28 bores. Robertson developed two versions of his hammerless sidelock; a tradtitional square body shape with beaded edges and a round body shape with no bead. This gun is of the former shape; the beaded edges of the square body highlighting the action filer's talent.

Another desirable feature of guns produced by Boss & Co. between WWI and WWII, was the wonderfully executed engraving. Jack Sumner’s expertly cut Rose & Scroll in Boss & Co.’s house pattern is showcased on this gun and leaves no doubt why it is so revered. The Maker’s name is engraved in a straight line along the leg of each lock plate as was the style after about 1925. 

The 26 1/2” chopper lump barrels remain in their original London proof with 2 3/4” chambers, both bore diameters measuring precisely .615” with .003” of choke in the right barrel and .008” in the left barrel. Smooth concave game rib features the 41 Albemarle St address which Boss & Co. occupied from 1930 to 1960. 

The original stock has a straight hand grip with traditional drop points, and a 14 1/4” LOP over a checkered butt. The splinter forend is fitted with Boss & Co.’s patented ejectors (No. 2988 of 1897) and an Anson pushrod. The forend and butt stock are checkered in a point pattern with Mullered borders. 

The gun remains complete in its original “violin” case with the Maker’s “13 Dover Street.” Address (occupied by Boss & Co. from 1908 to 1930) is marked out as was the practice at Boss & Co. after such address changes. 

The high overall condition and completeness of this gun is astounding with much of the original color hardening, barrel and furniture black and original oil stock finish remaining intact. The gun’s barrels have perfect bores and the ejectors are timed and strong. The trigger too works flawlessly with its distinctive “three-pull” system.

Looking at production numbers in Donald Dallas' comprehensive history on the firm, Boss & Co. Best Gunmakers, 2nd Edt. (2005), in 110 years (1891 - 2001), from the introduction of the Boss & Co. Hammerless Sidelock Ejector to the publication of the 2nd edition of Dallas' book, the firm had a total production of just 4,500 units. Of that total production, 3,941 were side-by-side hammerless shotguns produced in all bore sizes (e.g. 10, 12, 14, 16, 20, 28 and .410 bore). Only 260 were ever made in 20g.

A highly desirable, very rare gun from a maker who produced some of the finest guns ever made, in a wonderful configuration, and it remains in remarkably high, original condition. 

This gun exemplifies everything that makes best quality London sidelock shotguns from this era, especially those made by Boss &Co., so desirable. 

Simply an outstanding example of a between-the-wars Boss & Co. small bore shotgun and one of the finest vintage guns I have ever handled. 


Location US
Make Boss & Co.
Calibre/Gauge 20g
Action Sidelock
Triggers 1
Ejectors Yes
Barrel Length 26 1/2"
Rib Concave
Chamber 2 3/4"
Stock Straight
LOP 14 1/4"
Weight 5lbs 4oz
Case Maker's Lightweight Leather Case