Had a couple in both 12 and 20. As noted, the 12 is a very robust somewhat heavy gun, very well made and finished. I know of at least two 12's that were used to make double rifles and they performed flawlessly. Don't forget, these guns were made before choke tubes became common and they were intended for the American market as a nice all round side by side when such guns were still quite popular although fading fast. This meant stout tightly choked guns with 3" chambers intended to be used with heavy charges and big payloads of heavy lead shot for waterfowl. And they were great for that purpose until steel shot and choke tubes rendered them obsolete for waterfowl, almost overnight. The 20's were much trimmer and lighter and although still not a true lightweight they handled nicely and were (and still are) a fine alternative to the competition of the day from Beretta, Bernardelli, Ithaca/SKB and others and of course the Browning quality and value was there.
The BSS Sidelock is a completely different gun even though it shares the same name. It is a pure upland gun in concept and execution, light, trim and very well made. When new it was 4-5 times the price of the BSS, made in small quantities for a relatively short time. It was generally considered to be somewhat of a bargain for those who could afford it, being priced between the better quality Spanish sidelocks and the entry level British guns of the day but unfortunately came at a time when North American interest in side by sides was sinking fast. Current prices on these will still take you out of the comfort zone of many.
