That bugger who told you all this probably heard it from me!
I recommend that shooters NEVER clean their barrels, once they get their lead bullets working without leading. As BLHF stated, get my book, Jacketed Performance with Cast bullets. The name states it purpose for being, and points to precisely what the information in it is about. You'll learn about everything that effects lead bullet performance, how to make and use lead for various purposes, trouble shoot any problem and fix it quickly. Including how to clean lead from a bore quickly and easily. You may get some leading during your learning process, but if you use LBT bullet lube and follow my recommendations, you'll forget that little issue very quickly.
It isn't about modern lead bullets, because most commercial cast bullets still lead horribly with full handgun loads, and tend to be woefully inaccurate, by my standards, which quickly become the standards of readers of the above book. Also, keep in mind, if you buy LBT products I stand behind all my bragging, and will help walk any newcomers (and old pros) through their problems by personal email. Normally an email or two solves any problems, which are normally due to customers not clearly understanding all the literature I ship with my products, or my book.
For more info, hit the LBT website at LBTMoulds.com