I'm 99.999999999% certain that you have buildup in the chamber throat. Get a lead remover kit and scrub that puppy good.
I've never found "hard cast" bullets that were hard enough not to cause at least some leading. Factory barrels are worse in this regard because they are not polished as smooth inside as match barrels, and so they foul much faster.
Of course! Probably nobody here will agree with me by the best way I know to clean that dirty chamber is to get a .45 ACP bore brush (brass). Chuck it up in an electric drill. Saturate it with "Flitz" metal cleaner. Brush the piss out of the chamber.
Once you see how nasty that mother is, you will know what clean means.....shinny clean! After it is clean and chambering well, clean it meticulously after each firing. It won't be hard if you keep it cleaned as it fouls. A Q-Tip and a little "Flitz" will do the trick for routine maintenance......after it is clean to start with.
PigPen, While I'm not telling you what to do I don't think it's a good idea to tell everybody to go after their new toys with an electric tool. I've seen more damaged guns because some one wanted to take a shortcut and they ended up doing a "Tim the tool man" job on something.
Kevin, I bet that bbls fouled with lead alright. Get 'er clean and maybe use some FMJ instead. just a suggestion