I have had the same results at BC regarding chamber buildup in my .357.

If I shoot a bunch of .38s out of it, depending on the particular load, it is often times difficult and sometimes impossible to get a .357 into the cylinder. Normally a good cleaning takes care of this and I have never had to resort to a reamer to clean out the debris, however I could see how a much hotter .45LC could make the issue more pronounced.