Thought I'd share this on the forum. This is a small, twist on, LED that can be used as an inexpensive bore light for 50cal and up. With a bit of filing, it might fit down a 45cal. I wouldn't just drop it down the bore since that's how my last one died prematurely. Just hold the barrel at a low angle, put the light in, and raise the barrel to let it slide to the breech. At this price, $10 for 24, I plan on keeping them in pretty much any container that I carry for black powder.
https://www.amazon.com/Battery-Oper...d_r=f98fae04-4213-4993-82e2-2821eb1ca195&th=1
https://www.amazon.com/Battery-Oper...d_r=f98fae04-4213-4993-82e2-2821eb1ca195&th=1