Bar lock, back lock, these distinctions go back to muzzleloading guns when both types were available at the same time, sometimes from the same maker, particularly as percussion guns. In the final quarter of the nineteenth century (late 1800's) most of the prominent and stylish makers had settled on a single flagship action for their best guns and in the class conscious Britain of this time it was popular to follow the lead of the celebrity shooters of the day including the King and other nobility. These people and the guns they used were the sports stars of their day and if the King, or one of these top guns was using a Purdey or a Holland and Holland then this must be considered the best and to be strived for. Purdey with their Beesley self opening action, Holland and Holland with their Royal, Boss, Woodward, Grant and other prestigious makers all went with bar action guns for their best guns,Lancaster, Blanch and others settled on the back action as the way to go. The supposed advantage of the bar action was advertised as quicker lock time, crisper trigger pulls, less wood removal resulting in a stronger stock at the head. Back actions claimed stronger actions
because of less metal removal to accomodate the main spring, and sometimes sleeker lines. Generally back action guns could be manufactured a little cheaper than bar action guns because inletting metal was more laborious than inletting wood, so these guns could be priced a little lower in the line if a maker offered both types, leading again to the idea that the bar lock must be 'best' because it costs more. Generally both types made to the same standard will show no quantifiable advantage of one over the other. It is worth noting that for sidelock rifles where maximum strength is a factor as opposed to shotguns, the back action was and is preferred by most makers, especially in heavy calibers. Boxlocks are considered stronger than sidelocks in general and are seen much more frequently. Because back action guns can easily made with a bar action profile this has always been a popular version for those that prefer this style but few British makers make back action guns any more.