Frustrating-people don't read my posts. Wade, I was talking of corrosion after a period of time and MANY shooting sessions-not just one. if you take a lock and clean it every time, it doesn't matter how poor a seal you have. Conversly of you don't, and the TINYEST bit of corrosive nasty gets down there it reeks havoc.
Turtle
I read every post, Turtle. My locks, none of them, require any 'help' for sealing out the fouling. I will submit that if you use Pyrodex- corrosion from the perchlorate fouling will most certainly show up, if any fouling gets "in there". The locks come off the gun (except for the .69's percussion lock) ever time I shoot them, when I clean them - except the odd time at Hefley when the humidity is in the single digits. Then, I sometimes clean the rifle like LB- plug the vent, fill, set a shot spell, push that out and repeat for about 2 beer's time.
The 14 bore's lock has been off the rifle - may be 12 times since 1986 when she was built. There is never any fouling in the lock - every now and them - sometimes even once a year, I get curious and check it- no fouling and the hammer's cup is not corroded either.
With the rifle's bolster & snug fit of the rifle's parts, there is no fouling inside the lock- EVER. My flinters do not leak, either, but how would I know as you say - the locks are removed and get cleaned after every time I use them.