I have owned several Walthers over the years and none of them have ever had a problem with lead rounds except my PK380. For some reason, for lack of a better term, the "lip" that some lead rounds have tends to jam the feed from the magazine. I hear that it’s not an uncommon issue with the .380 pistols. I tried the .380 lead from Missouri Bullet which is where the problem manifested itself.
With lead rounds you also have to be more aware of the hardness of the lead alloy, the higher Brinell number the better, and in nearly all cases you should try to keep the load from exceeding 1000fps as the lead begins to melt at those speeds leaving lead deposits in the barrel.
Missouri Bullet sells a de-leading kit that I have read very good reviews about. It’s fairly cheap, somewhere in the area of $35 and well worth the investment if you intend to shoot a lot of lead.
Ron