I suspect many of you already know this, but I didn't see anything in the archives. My apologies if it's already common knowledge

The really small Maglight, "Solitaire", works perfectly as a bore light in .54 barrels. It's the one that uses a single AAA battery. Just twist it on, and slide down the barrel, lights up all the lands/grooves perfectly. Only costs about $6, and replacement batteries & bulbs are readily available.

Tomy chagrin, it won't quite fit down the barrel of my .50 caliber, but it has a fairly tight bore. If your .50 is a bit on the loose side, it might fit.

Yes it works perfect for the .54. I just wish it was a little smaller then I could use it in the .50 caliber as well. It sure beats a bore light all too....

THILL NITE LITE i am getting this week.

i will test it and update .

it may be best light for as small as 22 cal up to 62 cal,dont know until i test it.

cost is 3.49

Streamlight nanolight at bass pro. 1LED, 3 watch batteries, awesome bright, keychain snap. The head end is a little fat for 50 cal but I chuck it in the drill press and file it down. It's almost too bright to look at but a bit of paper tones it down.