I have read several articles and read some threads here regarding "slugging" a barrel with lead. My basic understanding of this process is to "push" a piece of lead through the entire barrel. I can see why one would do this to find the exact size of the bore and rifling, but what other information does this exercise give the shooter?

If the shooter is using cast bullets, this would give him/her the exact bore size so that the appropriate sized bullet can be used (.451 or .452 as an example). How will this process help the person who shoots strictly jacketed bullets? Am I missing something that I need to do to help with accuracy or anything else?

Thanks.

Really not needed in many cases for bore size...most modern cartridges and modern barrels are pretty close to the mark. Some older guns will be off-size...and MOST really old guns will be off today's standard size.

Considering the custom jacketed bullet makers, even jacketed bullets can come in various sizes.

But aside from just the diameter, the feel of pushing that lead slug doen the bore can give you some clues. Some barrels have tight spots or loose spots...you'll feel the added or reduced resistance to pushing the slug through. That information can be handing only if you intend to correct the poroblem...if the gun shoots well, would hesitate to fool with it.