Deposits inside cylinder

[Thumbcocker]

Why is it that some guns get deposits inside the cylinder right at the shiney ring where the brass stops and others don't ? My .45 colt with .4525 reamed cylinder mouths shooting .454 boolits gets deposits that are a bear to get out. My .44 with
.430 cylinder mouths shooting .431 boolits seldom gets the deposits and if it does they brush right out. All boolits are acww.

[Rico1950]

Try a .452" diameter boolit. Could be shaving lead with the .454".

[HeavyMetal]

Rico has it right! Your swaging under pressure every time you fire the gun and shearing off a little ring of lead.

Fire a bunch and the lead gets "cooked" into the "ridge" at the end of the case.