Boss & Co. is a name synonymous with quality, and as such they are among the most highly regarded names in the English arms trade. Every gun that they build is of the finest quality, making the title of author Donald Dallas' book ring true, "Boss & Co.: Best Gunmakers". A Boss & Co. brochure from the period this gun was built sums up their philosphy best: "We would say from the outset that we make only one grade of gun and have never placed a second quality make upon the market. This policy has enabled us to retain the services of the finest workmen in London, and to give them continuous employment. The advantages attending the production of best work only are manifold. There is no opportunity for the work of inferior men to be utilised in the economy of the workshop, which is frequently the case when more than one class of weapon is produced. The owner of a Boss & Co gun has the satisfaction of knowing that he has the best gun that money can buy, and that no one has a better gun. The Boss & Co gun has, therefore, always a standard value whether new or second hand. Our output is strictly limited according to the amont of first-class labour available." Blued steel barrels with a small post front sight (bead absent), a small sighting flat at the breech, "BOSS & Co., 13, DOVER STREET, PICCADILLY, LONDON, ENGLAND." marked on the upper barrel, London nitro proofs, scroll engraving at either side of the breech, and chambers proved at 2 1/2 inches with selective ejectors. The casehardened Boss patent sidelock action displays masterfully executed English style bouquet & scroll engraving which surrounds the Boss patent numbers on the triggerplate and both sides of the receiver as well as "BOSS & Co." signed on either lockplate. The wonderful engraving was likely executed by Jack G. Sumner who became Boss's full-time engraver in 1920 after returning from World War One. The exceptionally fine engraving extends to the toplever, triggerguard, and both of the tangs, both of which show engraved screw heads. The gun features a single non-selective trigger, gold inlaid cocking indicators, a right hand rolled triggerguard, and a tang mounted automatic safety switch with gold inlaid "SAFE". Exquisite, highly figured, multi-point checkered forend with engraved fittings, including the Anson button release and Boss patent shoe, and straight grip stock with carved teardrop flats, inscription oval marked with the initials "F.A.M.", and a checkered bare butt. The gun was built at the start of the Golden Age of British gunmaking between 1926 and 1930 per page 325 of Donald Dallas' above mentioned book which also notes only 76 20-bore over/unders being produced by the company on page 318, with even fewer with a single trigger, making this a very hard to find best quality gun. Barrel and stock measurements for original set (U/O): bore diameter nine inches from the breech both proved at "20" (.615 inches) and measured .621/.621 inches; choke constriction .009/.004 inches; minimum wall thickness .029/.027 inches; 1 9/16 inch drop at comb; 2 5/16 inch drop at heel; 14 7/16 inch length of pull; weight 5 lbs. 7 oz.

Very fine, retaining 90% of the original blue finish on the barrels with the loss concentrated near the muzzles, 50% original blue on the triggerguard, nearly all of the original blue on the toplever, and 60% plus original case colors on the action. The metal shows light handling evidence and a few tiny areas of minor spotting. The wood is also very fine with some smaller dings and scratches, a small splice repair at the toe, and crisp checkering at the forend and wrist. Mechanically excellent.