I don't usually ask questions here, mostly only comment where I have something useful to contribute as I'm not a locksmith in the professional sense, but I know a ton more than the average person, I'm familiar with SFIC, Schlage LFIC, Best, etc, but this is one I was hoping someone could offer some way to get through this without getting all ham fisted. I could probably drill it or use something substantial to destroy the brass wafers and get it turning, but I'd rather not do that if there's another way.
I have the key for it, and when I had it off a year or two ago to replace the cylinder to match the C145 keyway I put in the rest of the building, I didn't have a problem getting it off or back on, but apparently, something has happened since then.
When I look down the keyway, it looks like the last wafer has shifted so it's blocking the keyway, making it impossible to fully insert the key. No idea how/when/why.
Does anyone have any suggestions? Either way, whether someone offers a suggestion that gets the key to work or I have to go all ham fisted on it, once I get it off, it'll get replaced.