About 25-30 years ago I loaded some shells with black to use in a hammer gun I had at the time. That fun soon wore off for me, as I was shooting lots of black in m/loaders too. A full box of those shells were in my shop, leftover, in a regular shell box.
I hosted a dove shoot and one of the guests had forgotten shells. His father asked if I had any extra. I looked in the shop, saw those leftovers and handed them to him, not realizing they were loaded with black.
He was shooting an A5, AIR, and after the fun commenced he walked over to his Dad and showed him his gun, which had stopped functioning. His Dad, a m/l shooter too and familiar with black powder fouling, looked at the gun and immediately diagnosed the problem, partly by the smell.
We all had a big laugh about it. His son had never even noticed all the extra smoke.
