When choke boring became fasionable in England many years ago the proof houses began stamping the bbls "Not for Ball". W W Greener fully explained the reason for this at some point prior to 1910. The reason being it had been common practise to use balls very close to bore size for better accuracy which were too large to pass through the choke. He further explained it was quite OK to shoot solid balls as long as they were sized to pass through the choke. The British proof houses for this reason changed the marking FROM "Not for Ball" to simply "Choke". The standard for round balls loads became of a size which would pass through full chokes & was in universal use in the US for some years until the Foster Slug came on the market. As mentioned it was dimensioned to pass through any normal full choke.
Man; Millions of these have been fired over the ensuing years, there's not much a 74 yr old man could do in one year that would make much of a difference difference. Actually when one is aware of "History" there is little need to re-live it.
If you have some new-fangled slug load & the maker says Do not use in full choke guns, then I would heed the warning. I would have no qualms of using a Foster or Brenneke slug through a full choke as long as the shell was loaded to an acceptable pressure level for the gun at hand. Its been done for more years than I care to remember. Personally I prefer a good rifle & would only use a slug at all if in an area where the law required it.
