For those wondering how on earth you can bend the base pin while shooting, the short answer is - you can't.
But you CAN bend the base pin while loading.
Here's how to do it, if you really want to.
For one reason or another - maybe to free up a stuck cap fragment - whatever - you take the gun apart and remove the cylinder. You clear the stoppage/remove the fragment of cap [or whatever] and put it all back together again.
Except that Joe next door talks to you, and asks to borrow your something or other. Handing it to him, you miss turning the locking bolt into position. All LOOKS fine.
Having put the gun on half-cock, you then fill up each chamber until all five/six are ready to take the ball. YMMV.
You put the ball in the chamber mouth and try to ram it into the chamber.
Instead of the ball going in, the loading lever, with it's head firmly located on top of the unmoving ball which then acts as a fulcrum, and base pin rise up out of the unlocked position, clear of the front of the frame and you, still bearing down on the loading lever, bend it at the weakest point - where the locking bolt cut-out is located. with luck [bad luck, on this occasion] you might just break it there, in which case you are futzed.
You have now bent your first base pin!
PLEASE do not try to do this unless you have a supply of unbent base pins. My replacement came from the usual on-line market for a tad under £40.