"the gun trade is very secretive...."

Read my previous post again.



There was a very early 20th century, pre first world war, trade magazine called Arms and Explosives? I read an article in an edition which detailed in several pages experiments carried out by BSA using the Lincoln Jeffries patent underlever rifles they were making at the time. They experimented with light and heavy pistons eventually settling on the heavy for best overall performance in their production air rifles

That doesn't sound very secretive to me
As well as I can remember JB gave details in Airgun World of what he did in his air rifle conversions including information about piston heads, weights transfer port sizes, barrel locks, adjustable hinge bolts etc. Is there anything specific you want me to ask him tomorrow? Why don't you ring him and seek his advice yourself? It would save me the cost of a phone call