LEAVE IT ALONE, the .45 is GREAT for deer. 90% of the over 200 I have taken with a ML has been with a .45 flinter.
I question the .440" thing though. A .45 will be .450" across the lands and a .445" ball is best but I use .450" with a .010" patch.
Get the land to land measured so you don't use a ball too small.
TC started the smaller ball junk for their barrels but they still shot better with the right size.
