I'm sure you were expecting someone to make this comment, but I'm going to say it anyway:
Spend the extra few minutes to clean properly after shooting corrosive ammunition.
I don't know much about the new oils/preservatives on the market these days as I've been using nothing other than Hoppe's 9 and sometimes CLP if it's going to be sitting for a while. However, I can tell you that a good friend of mine blames regular Hoppe's #9 for failing to neutralize the corrosive salts in his 91/30 Nagant after shooting a few boxes of Czech silver tip steel-core FMJs. Of course, he should be blaming himself as Hoppes never claimed that product would neutralize corrosive agents. It pains me to say, but the corrosion was due to his laziness, simple as that. I suppose shifting the blame helped him cope... who knows.
I've never understood the complaints I've heard from others after they've had to swab the barrel with hot soapy water and dry paper towels before a regular cleaning after they've intentionally purchased berdan-primed ammunition to save money. I suppose now you can buy specialty oils to do the job for you... but I'm guessing they'll cost more.
You gotta pay somehow, sometime.